meillo@92: \chapter{Market analysis}
meillo@105: \label{chap:market-analysis}
meillo@92: 
meillo@123: This chapter analyzes the current situation and future trends, for electronic communication in general and email in particular. First electronic mail's position within other electronic communication technologies is located. Then trends for the whole field of electronic communication are shown. Afterwards opportunities and threats in the market are located and trends for email are figured out. The insights of these analysis result in a summary of things that are important for developing future-prove email software.
meillo@92: 
meillo@92: 
meillo@92: 
meillo@105: \section{Electronic communication technologies}
meillo@92: 
meillo@114: Electronic communication is ``communication by computer'', according to the \name{WordNet} database of \name{Princeton University} \citeweb{wordnet}. Mobile phones and telefax machines should be seen as computers here too. The \name{Science Glossary} of the \name{Pennsylvania Department of Education} describes electronic communication as ``System for the transmission of information using electronic technology (e.g., digital cameras, cellular telephones, Internet, television, fiber optics).'' \citeweb{science-glossary-pa}.
meillo@92: 
meillo@114: Electronic communication needs no transport of tangible things, only electrons, photons, or radio waves need to be transmitted. Thus electronic communication is fast in general. With having costs mainly for infrastructure and very low costs for data transmission, electronic communication is also cheap communication. As underlying transport infrastructure, mostly the Internet is used; this makes it available nearly everywhere around the world. These properties---fast, cheap, everywhere---make electronic communication well suited for long distance communication.
meillo@92: 
meillo@105: As globalization proceeds and long distance communication becomes more and more important. The future of electronic communication is bright.
meillo@92: 
meillo@123: Electronic communication includes the following technologies: electronic mail (email), instant messaging (\name{IM}), chats (e.g.\ \NAME{IRC}), short message service (\NAME{SMS}), voice mail, video messages, and Voice over \NAME{IP} (\NAME{VoIP}).
meillo@92: 
meillo@92: 
meillo@105: \subsection{Classification}
meillo@123: Types of electronic communication can be divided in synchronous and asynchronous communication. Synchronous communication is direct dialog with little delay. Telephone conversation is an example. Asynchronous communication consists of independent messages. Dialogs are possible as well, but not in the same direct fashion. These two groups can also be split by the time needed for data delivery. Synchronous communication requires nearly real-time delivery, whereas for asynchronous communication message delivery times of several seconds or even minutes are sufficient.
meillo@92: 
meillo@123: Another possible separation is to distinguished written and recorded information. Recorded information, like audio or video data, is accessible only in a linear way by spooling and replay. Written information, on the other hand, can be accessed in arbitrary sequence, detail and speed.
meillo@114: 
meillo@132: \person{Lenke} and \person{Schmitz} \cite{lenke95} use the same criteria to classify \emph{new media}. %fixme: is this term common?
meillo@123: They additionally divide into local and remote communication---the latter is presumed here---and by the number of communication participants. As communication technologies for n:m communication (like chat rooms) are usable for 1:1 too (private chat), and ones for 1:1 (email) are usable for n:m (mailing lists), a classification by participant structures is omitted here.
meillo@92: 
meillo@123: Figure \ref{fig:comm-classification} shows a classification of communication technologies sorted by the properties synchronous/asynchronous and written/recorded. Email and \NAME{SMS} are written and asynchronous communication; \NAME{IM} and chats are written information too, but synchronous. Recorded information are voice mail and video messages as examples for asynchronous communication. VoIP is an example for synchronous communication.
meillo@92: 
meillo@123: One might be surprised to find Instant \emph{Messaging} not in the group of \emph{message} communication. Instant Messaging could be put in both groups because it allows asynchronous communication additional to being a chat system. The reasons why it is sorted to dialog communication are its primary use for dialog communication and the very fast---instant---delivery time.
meillo@92: 
meillo@123: Email is not limited to written information, at least since the advent of \NAME{MIME}, which allows to include multimedia content in textual email messages. Thus recorded information can be sent as sub parts of emails. The same applies to Instant Messaging too, where file transfer is an additional sub service offered by most systems. In general recorded information can be transmitted in an encoded textual form.
meillo@92: 
meillo@105: 
meillo@105: 
meillo@105: \input{kvmacros}
meillo@105: \kvunitlength=3cm
meillo@105: \kvnoindex
meillo@105: 
meillo@126: \begin{figure} %fixme: table or figure?
meillo@105: 	\begin{center}
meillo@126: 		\input{input/comm-classification.tex}
meillo@105: 	\end{center}
meillo@105: 	\caption{Classification of electronic communication}
meillo@105: 	\label{fig:comm-classification}
meillo@105: \end{figure}
meillo@105: 
meillo@105: 
meillo@105: 
meillo@105: 
meillo@105: \subsection{Life cycle analysis}
meillo@123: Life cycle analysis are common for products but also for technologies. This one here is for electronic communication technologies. The first dimensions regarded is the life time of the subject. It is segmented into the introduction, growth, mature, saturation, and decline phases. The second dimension can display sales, market share, importance, or similar values. The graph has always an S-line shape, with a slow start, a rapidly increasing first half, the highest level in the third quarter, and a slowly declining end. Reaching the end of the life cycle means, the subject is inherited by its successor or the market situation changed thus making it old fashioned.
meillo@105: 
meillo@105: The current position on the life cycle of the introduced communication technologies is depicted in figure \ref{fig:comm-lifecycle}. It is important to notice that there is no time line matching for all of them---some life cycles are shorter than others---the shape of the graph, however, is the same.
meillo@105: 
meillo@123: Video messages and voice mail are technologies in the introduction phase. Voice over \NAME{IP} is heavily growing these days. Instant Messaging has reached maturation, but still growing. Email is an example for a technology in the saturation phase. Declining does none of the above mentioned; telefax is an example for a declining technology.
meillo@105: 
meillo@105: \begin{figure}
meillo@105: 	\begin{center}
meillo@126: 		\input{input/comm-lifecycle.tex}
meillo@105: 	\end{center}
meillo@105: 	\caption{Life cycle of electronic communication technologies}
meillo@105: 	\label{fig:comm-lifecycle}
meillo@105: \end{figure}
meillo@105: 
meillo@105: Email ranges in the saturation phase, which is defined by a saturated market, no more products are needed, there is no more growth. This means, email is a technology used by everyone who want to use it. It is a standard technology. The current form of email in the current market is on the top of its life cycle. The future is decline, sooner or later.
meillo@105: 
meillo@120: But life cycles positions change as the subject or the market changes. An examples is the \name{Flash} animation software. The product's change from a drawing and animation system to a technology for website building, advertising, and movie distribution, and the then changing target market, made it slip back on the life cycle. If the email system would evolve to become the basis for Unified Messaging (see section \ref{sec:unified-messaging}), a similar slip back would be the consequence. An example for a changing market are the \NAME{DVD} standards \NAME{DVD+} and \NAME{DVD$-$}. With the upcoming next generation formats BlueRay and \NAME{HD-DVD}, a much sooner decline of \NAME{DVD+} and \NAME{DVD$-$} started, even before reaching their last development steps in storage size. Such can happen to email too, if Unified Messaging is a revolution to the email system instead of an evolution.
meillo@105: 
meillo@105: 
meillo@105: 
meillo@105: 
meillo@105: \subsection{Trends}
meillo@107: Following are the trends for electronic communication. The trends are shown from the view point of \mta{}s. Nevertheless are these trends common for all of the communication technology.
meillo@105: 
meillo@105: \subsubsection*{Consolidation}
meillo@123: There is a consolidation of communication technologies with similar transport characteristics, nowadays. Email is the most flexible kind of asynchronous communication technology already in major use. Hence email is the best choice for transferring messages of any kind today. But in future it probably will be \name{Unified Messaging}, which tries to group all kinds of asynchronous messaging into one communication system. It aims to provide a single transport protocol for all content and a flexible access interface for all kinds of clients. Unified messaging seems to have the potential to be the successor of all asynchronous communication technologies, including email.
meillo@105: 
meillo@123: Today email still is the major asynchronous communication technology and it probably will be it for the next years. As Unified Messaging needs similar transfer facilities to email, it may to be an evolution not a revolution. Hence \mta{}s will still have importance in future, maybe in a modified way.
meillo@105: %todo: decentral organization, like the internet -> MTAs are well suited -> further technologies will need something similar
meillo@105: 
meillo@105: 
meillo@105: \subsubsection*{Integration}
meillo@123: Integration of communication technologies becomes popular. This goes beyond consolidation, because communication technologies of different kinds are bundled together to make communication more convenient for human. User interfaces tend to this direction. The underlying technologies will get grouped, but it seems as if synchronous and asynchronous communication can not be joined together in a sane way, so they will probably only merge at the surface.
meillo@105: 
meillo@105: 
meillo@105: 
meillo@105: \subsubsection*{Communication hardware}
meillo@105: Hardware needed for communicating comes from two different roots: On the one side, the telephone, now available as mobile phones. This group centers around recorded data and dialog, but messages are supported by the answering machine and \NAME{SMS}. On the other side, mail and its relatives like email, using computers as main hardware. They center around document messages, support dialog communication in Instant Messaging and Voice over \NAME{IP}.
meillo@105: 
meillo@114: The last years finally brought the two groups together, with \name{smart phones} being the merging hardware element. Smart phones are computers in the size of mobile phones or mobile phones with the capabilities of computers, however one likes to see it. They provide both functions, being telephones and computers.
meillo@105: 
meillo@114: Smart Phones match well the requirements of recorded data, for which they were designed. Writing text is not good to do with the minimal keyboards available for smart phones; speech to text converters may provide help in future. This leaves us with the need for ordinary computers for the field of exchanging documents and as better input hardware for all written information.
meillo@105: 
meillo@123: It seems as if a combination of computers and smart phones will be the hardware used for communication in future. Both specialized to the best matching communication technologies, but supporting the others too. Hence facilities for transferring information off and onto the devices will be needed.
meillo@105: 
meillo@105: 
meillo@105: 
meillo@114: \subsubsection*{Unified Communication}
meillo@120: \name{Unified communication} is the technology aiming to consolidate and integrate all electronic communication and providing access for all kinds of hardware clients. Unified communication tries to bring the tree trends here mentioned together. The \name{{\smaller PC} Magazine} has the following definition in its Encyclopedia \citeweb{pcmag:uc}: ``[Unified communications is] The real-time redirection of a voice, text or e-mail message to the device closest to the intended recipient at any given time.'' The main goal is to integrate all kinds of communication (asynchronous and synchronous) into one system, hence this requires real-time delivery of data.
meillo@114: 
meillo@142: According to Michael \person{Osterman} \citeweb{howto-def-uc}, unified communications is already possible as far as various incoming sources are routed to one storage where messages can be accessed by one or a few clients. But a system with an ``intelligent parser of a single data stream into separate streams that are designed to meet the real-time needs of the user'' is a goal for the future, he says.
meillo@114: 
meillo@123: The question is, if the integration of synchronous and asynchronous message transfer does make sense. A communication between one person talking on the phone and the other replying using his instant messenger, certainly does, if the text-to-speech and speech-to-text converting is fast and the quality good enough. But transferring large video messages and real-time communication data with the same technology, possibly does not.
meillo@114: 
meillo@114: 
meillo@114: 
meillo@114: \subsubsection*{Unified Messaging}
meillo@114: \label{sec:unified-messaging}
meillo@123: \name{Unified messaging}, although often used exchangeable with unified communications, is only a subset of it. It does not require real-time data transmission and is therefor only usable for asynchronous communication \citeweb{wikipedia:uc}. Unified messaging's function is basically: Receiving incoming messages from various channels, converting it to a common format, and storing it into a single space. The stored messages can then be accessed from different devices. \citeweb{wikipedia:um}
meillo@114: 
meillo@114: The easiest way of unified messaging is to base it on either email and convert all input sources to email messages (as attachments for instance) and store them in the user's mail box. Or use the telephone system as basis and convert text messages to speech. Both is no problem for asynchronous communication.
meillo@114: 
meillo@148: Finally a critical voice from Jesse \person{Freund}, who voted unified messaging on top of a hype list for \name{Wired.com}, ten years ago \cite{wired:hype}. His description of the technology ended with the humorous sentences: ``Unified messaging is a nice idea, but a tough sell: The reason you bought a cell phone, a pager, and a fax/modem is because each does its job well. No one wants to download voice mail as a series of RealAudio messages or sit through a voice mail bot spelling out email, complete with `semicolon dash end-parenthesis' for ;-).''
meillo@114: 
meillo@114: 
meillo@114: %todo: have a result here?
meillo@105: 
meillo@105: 
meillo@105: 
meillo@105: 
meillo@105: \section{Electronic mail}
meillo@105: 
meillo@123: After viewing the whole market of electronic communication, a zoom in to the market of electronic mail follows. Email is an asynchronous communication technology that transports textual information primary. This thesis is about a \mta, so the market situation for email is important. Interesting questions are: Is email future-safe? How will electronic mail change? Will it change at all? Which are the critical parts? These questions matter when deciding on the directions for further development of an \MTA. They are discussed in this section.
meillo@107: 
meillo@105: 
meillo@105: 
meillo@120: \subsection{SWOT analysis}
meillo@105: 
meillo@123: A \NAME{SWOT} analysis regards the strengths and weaknesses of a subject against the opportunities and threats of its market. The slightly altered form called \name{Dialectical {\smaller SWOT} analysis}, which is used here, is described in \cite{powerof2x2}. \NAME{SWOT} analysis should always focus on a specific specific goal to reach with the product. In this case, the main goal is to make email future-safe.
meillo@105: 
meillo@123: The market's main threat is \emph{spam}, also named \name{junk mail} or \name{unsolicited commercial email} (\NAME{UCE}). Panda Security and Commtouch state in their \name{Email Threats Trend Report} for the second Quarter of 2008: ``Spam levels throughout the second quarter averaged 77\%, ranging from a low of 64\% to a peak of 94\% of all email [...]''\cite[page 4]{panda:email-threats}. The report sees the main reason in the bot nets consisting of zombie computers: ``Spam and malware levels remain high for yet another quarter, powered by the brawny yet agile networks of zombie \NAME{IP}s.''\cite[page 1]{panda:email-threats} This is supported by IronPort Systems: ``More than 80 percent of spam now comes from a `zombie'---an infected \NAME{PC}, typically in a consumer broadband network, that has been hijacked by spammers.''\cite{ironport:zombie-computers}. Positive for \MTA{}s is, that they are not the main source for spam, but it is only a small delight. Spam is a general weakness of the email system, because it can not prevent it.
meillo@105: 
meillo@126: \begin{quote}
meillo@126: Since receivers pay the bulk of the costs for spam (including most obviously their time to delete all that incoming spam), spam use will continue to rise until effective technical and legal countermeasures are deployed, or until people can no longer use email.
meillo@126: \url{http://www.dwheeler.com/guarded-email/guarded-email.html}
meillo@126: \end{quote}
meillo@126: 
meillo@123: Opportunities of the market are large data transfers, coming from multimedia content, which becomes popular. If email is used as basis for unified messaging, lots of voice and video mail will need to be transferred. Email is weak related to that kind of data: the data needs to be encoded to \NAME{ASCII} and and stresses mail servers a lot.
meillo@114: 
meillo@114: The use of various hardware to access mail is another opportunity of the market. The software and infrastructure needed to transfer mail within this network might be a weakness of the email system. %fixme: think about that
meillo@114: 
meillo@114: An opportunity of the market and at the same time a strength of electronic mail is its standardization. Few other communication technologies are standardized and thus freely available in a similar way. %fixme: ref
meillo@123: Another opportunity and strength is the modular and extensible structure of electronic mail; it can easily evolve to new requirements. %fixme: ref
meillo@105: 
meillo@123: The increasing integration of communication channels, is an opportunity for the market. But deciding weather it is a weakness or strength of email is not so easy. It is a weakness because the not possible integration of stream data and the not good integration of large binary data. It is also a strength, because arbitrary asynchronous communication data already can be integrated. On the other hand, the integration might be a threat too, because it easily leads to complexity of software. Complex software is more error prone and thus less reliable. This could be a strength of electronic mail because of its modular design that decreases complexity, but real integration is harder to do than in monolithic systems.
meillo@105: 
meillo@107: Figure \ref{fig:email-swot} displays the \NAME{SWOT} analysis in a handy overview. It is easy to see, that the opportunities outweigh. This indicates a still increasing technology. %fixme: ref
meillo@105: 
meillo@105: \begin{figure}
meillo@105: 	\begin{center}
meillo@126: 		\input{input/email-swot.tex}
meillo@105: 	\end{center}
meillo@120: 	\caption{\NAME{SWOT} analysis for email}
meillo@105: 	\label{fig:email-swot}
meillo@105: \end{figure}
meillo@105: 
meillo@105: The analysis shows what should be done to achieve the goal (Making email future-safe). Spam mail should be reduced as good as possible. Solutions for large data transfers and infrastructures with more nodes moving within the net should be developed, there is a lot of potential. Standardization, modularity and extendability should be used to go even further, these are the key advantages of email.
meillo@115: %fixme: a bit more concrete, see description of swot analysis
meillo@105: 
meillo@105: 
meillo@105: 
meillo@92: 
meillo@92: \subsection{Trends for electronic mail}
meillo@92: 
meillo@107: Trends and possible trend, or just plans to think about, are presented now.
meillo@107: %Emailing in future will not be the same as emailing today. This will mainly affect how email is transfered.
meillo@105: 
meillo@105: 
meillo@107: \subsubsection*{Provider independence}
meillo@122: Today's email structure is heavily dependent on email providers. This means, most people have email addresses from some provider. These can be the provider of their online connection (e.g.\ \NAME{AOL}, \name{T\mbox{-}On\-line}),
meillo@114: %fixme: check for non-breakable dash
meillo@114: freemail provider (e.g.\ \NAME{GMX}, \name{Yahoo}, \name{Hotmail}) or provider that offer enhanced mail services that one needs to pay for. Outgoing mail is send either with the webmail client of the provider or using \name{mail user agent}s sending it to the provider for relay. Incoming mail is read with the webmail client or retrieved from the provider via \NAME{POP3} or \NAME{IMAP} to the local computer to be read in the \name{mail user agent}. This means all mail sending and receiving work is done by the provider.
meillo@92: 
meillo@123: The reason therefor is originated in the time when people used dial-up connections to the Internet. A mail server needs to be online to receive email. Sending mail is no problem, but receiving it is hardly possible with an \MTA\ being few time online. Internet service providers had servers running all day long connected to the Internet. So they offered email service.
meillo@92: 
meillo@123: Nowadays, dial-up Internet access is rare; the majority has broadband Internet access paying a flat rate for it. So being online or not does not affect costs anymore, even traffic is unlimited. Today it is possible to have an own mail server running at home. The last technical problem remaining are the changing \NAME{IP} addresses one gets assigned every 24 hours. But this is easily solvable with one of the dynamic \NAME{DNS} services around; they provide the mapping of a fixed domain name to the changing \NAME{IP} addresses.
meillo@92: 
meillo@123: Home servers become popular in these days, for central data storage and multimedia services. Being assembled of energy efficient elements, power consumption is no big problem anymore. These home servers will replace video recorders and music collections in the near future. It is also realistic that they will manage heating systems and intercoms too. Given the future leads to this direction, it is a logical step to have email and other communication will be provided by the (or one of) the own server as well.
meillo@92: 
meillo@92: After \mta{}s have not been popular for users in the last time, the next years might bring them back to them. Maybe in a few years nearly everyone will have one running at home \dots\ possibly without knowing about it.
meillo@92: 
meillo@92: 
meillo@92: \subsubsection*{Pushing versus polling}
meillo@92: The retrieval of email is a field that is about to change now. The old way is to fetch email by polling the server that holds the personal mail box. This polling is done in regular intervals, often once every five to thirty minutes. The mail transfer from the mail box to the \name{mail user agent} is initiated from the mail client side. The disadvantage herewith is the delay between mail actually arriving on the server and the user finally having the message on his screen.
meillo@92: 
meillo@123: To remove this disadvantage, \name{push email} was invented. Here the server is not polled every few minutes about new mail, but the server pushes new mail directly to the client on arrival. The transfer is initiated by the server. This concept became popular with the smart phones; they were able to do emailing, but the traffic caused by polling the server often was expensive. The concept works well with mobile phones where the provider knows about the client, but it seems not to be a choice for computers since the provider needs to have some kind of login to push data to the computer.
meillo@92: 
meillo@123: The push concept, however could swap over to computers when using a home server and no external provider. A possible scenario is a home server receiving mail from the Internet and pushing it to computers and smart phones. The configuration could be done by the user through some simple interface, like one configures his telephone system to have different telephone numbers ring on specified phones.
meillo@92: %FIXME: add reference to push email
meillo@92: 
meillo@105: 
meillo@126: \subsubsection*{New email protocols}
meillo@126: 
meillo@142: Another concept to redesign the electronic mail system, but this time focused on mail transfer is named ``Internet Mail 2000''. It was proposed by \person{Daniel~J.\ }{Bernstein}, the creator of \qmail. Similar approaches were independently introduced by others too.
meillo@92: 
meillo@123: As main change it makes the sender have the responsibility of mail storage; only a notification about a mail message gets send to the receiver, who can fetch the message then from the sender's server. This is in contrast to the \NAME{SMTP} mail architecture, where mail and the responsibility for it is transferred from the sender to the receiver.
meillo@92: 
meillo@123: \name{Mail transfer agent}s are still important in this mail architecture, but in a slightly different way. Their job is not transferring mail anymore---this makes the name misleading---they are used to transport the notifications about new mail to the destinations. This is a quite similar job as they do in the \NAME{SMTP} model. The real transfer of the mail can be done in any way, for example via \NAME{FTP} or \NAME{SCP}.
meillo@92: %FIXME: add references for IM2000
meillo@92: 
meillo@92: 
meillo@126: %add ``guarded email'' by dwheeler
meillo@126: 
meillo@126: %maybe add a third one
meillo@92: 
meillo@92: 
meillo@105: 
meillo@114: \subsection{Future-safety of email}
meillo@115: %fixme: rework
meillo@123: It seems as if electronic mail or a similar technology has good chances to survive the next decades. This bases on the assumption that it always will be important to send information messages. These can be notes from other people, or notifications from systems (like a broken or full hard drive in the home server, or the coffee machine ran out of coffee beans). Other communication technologies are not as suitable for this kind of messages, as email, short message service, voice mail, and the like. Telephone talks are more focused on dialog and normally interrupt people. These kind of messages should not interrupt people, unless urgent, and they do not need two-way information exchange. The second argument applies to instant messaging too. If only one message is to be send, one does not need instant messaging. Thus, one type of one-way message sending technology will survive.
meillo@114: 
meillo@114: Whether email will be the one surviving, or short message service, or another one, does not matter. Probably it will be \name{unified messaging}, which includes all of the other ones in it, anyway. \MTA{}s are a kind of software needed for all of these messaging methods---programs that transfer and receive messages.
meillo@114: 
meillo@148: \subsubsection*{Unified Communication}
meillo@148: Integration of asynchonous with synchronous communication channels is what Unified Communication is about. It seems not be possible to merge the two worlds on basis of email in an evolutionary way. As only a revolutionary change of the whole email concept would make it possible, it is best to ignore it. New designed technologies are usually superior to heavily patched and bent old technologies anyway. A general merge of synchronous and asynchronous communication has good chances to be fatal for email.
meillo@148: 
meillo@148: Until Unified Communication will become reality---if ever---electronic mail has a good position, also as basis for Unified Messaging.
meillo@114: 
meillo@114: 
meillo@114: 
meillo@105: 
meillo@105: \section{What will be important}
meillo@126: \label{sec:what-will-be-important}
meillo@110: Now that it is explained why email will survive (in some changed but related form), it is time to think about the properties required for \mta{}s in the next years. Because as the fields and kinds of usage change, the requirement change too.
meillo@92: 
meillo@123: Provider independence through running an own mail server at home asks for easy configuration of the \MTA. Providers have specialists to configure the systems, but ordinary people do not. Solutions are either having some home service system for computer configuration established with specialists coming to ones home to set up the systems; like it is already common for problems with the power and water supply systems. Or configuration needs to be easy and fool-prove, to be done by the owner himself. The latter solution depends on standardized parts that fit together seamlessly. The technology must not be a problem itself. Only settings custom to the users environment should be left open for him to set. This of course needs to be doable using a simple configuration interface like a web interface. Non-technical educated users should be able to configure the system.
meillo@92: 
meillo@132: Complex configuration itself is not a problem if simplification wrappers around it do provide an easy interface. The approach of wrappers to make it look easier to the outside is a good concept in general. %FIXME: add ref
meillo@132: It still lets the specialist do complex and detailed configuration, and also offering a simple configuration interface to novices. \sendmail\ took this approach with the \name{m4} macros. %fixme: add ref
meillo@132: Further more is it well suited to provide various wrappers with different user interfaces (e.g.\ graphical programs, websites, command line programs; all of them either in a questionnaire style or interactive).
meillo@92: 
meillo@110: When \MTA{}s become popular on home servers and maybe even on workstations and smart phones, then performance will be less important. Providers need \mta{}s that process large amounts of mail in short time. Home servers or workstations however, do not see that much mail; they need to handle only tens or hundreds of email messages per hour. Thus performance will probably not be a main requirement for an \MTA\ in future, if they mainly run on private machines.
meillo@92: 
meillo@110: New mailing concepts and architectures like push email or \name{Internet Mail 2000} will, if they succeed, require \mta{}s to adopt the new technology. \MTA{}s that are not able to change are going to be sorted out by evolution. Thus it is important to not focus too much on one use case, but to stay flexible. Allman saw the flexibility of \sendmail\ one reason for its huge success (see section \ref{sec:sendmail}).
meillo@92: 
meillo@110: Another important requirement for all kinds of software will be security. There is a constant trend coming from completely non-secured software, in the 70s and 80s, over growing security awareness, in the 90s, to security being a primary goal, now. This leads to the conclusion that software security will be even more important in the next years. As more clients get connected to the Internet and especially more computers are listening for incoming connections (like an \MTA\ in a home server), there are more possibilities to break into systems. Securing of software systems will be done with increasing effort in future.
meillo@92: 
meillo@105: ``Plug-and-play''-able hardware with preconfigured software running can be expected to become popular. Like someone buys a set-top box to watch Pay-\NAME{TV} today, he might be buying a box acting as mail server in a few years. He plugs the power cable in, inserts his email address in a web interface and selects the clients (workstation computers or smart phones) to which mail should be send and from which mail is accepted to receive. That's all. It would just work then, like everyone expects it from a set-top box today.
meillo@92: 
meillo@110: Secure and robust software is a pre-requisite for such boxes to make that vision possible.
meillo@92: 
meillo@132: It seems as if all widely used \mta{}s provide good security nowadays. The modular architecture is generally seen to be conceptually more secure, however.
meillo@92: 
meillo@123: In summary: Easy configuration, as well as the somehow opposed flexibility will be important for future \mta{}s. Also will it be security, but not performance. \MTA{}s might become more commodity software, like web servers already are today, with the purpose to include it in many systems and the need of minimal configuration.
meillo@92: 
meillo@92: 
meillo@92: 
meillo@133: 
meillo@146: % Chapter \ref{chap:market-analysis} dealt with this topic. The trends for the communication market were consolidation, integration and a merge of communication hardware. All this goes along with market's change to Unified Messaging and later Unified Communication. Electronic mail appears to have good chances to stay an important transport technology then: It can transport all kinds of asynchronous messages and email usage from desktop computers and mobile devices is already established. Hence electronic mail is ready for Unified Messaging. Unified Communication, however, requires more, including the integration of synchronous communication channels with asynchronous ones. This is a point where email does bad. The \emph{store-and-forward} transport architecture of email is not suited for synchronous data transfer. Until, if ever, Unified Communications becomes reality, email is a winner.