That last part is very important. People sometimes think that IM clients are chosen for their technical excellence or features. No, they're not. Forthcoming research from Ferris Research shows conclusively that we choose our IM clients based on what services our friends and coworkers are already using.
If it's for business, many other factors come into play, such as security, message archiving, logging, and interoperability. Even so, I suspect that the services that the CIOs and CEOs use at home probably get as serious a look as the corporate IM packages.
Linux IM clients do tend to have fewer features than their Windows counterparts. On the other hand, some IM users aren't crazy about IM clients that include video conferencing, file transfers, games, N'Sync wallpaper, and the kitchen sink. If all you really want is good, solid IM service that will let you talk to the people you want to talk to, then there's sure to be a Linux IM client for you.
While this isn't a comprehensive survey of Linux IM clients (by my count, there are at least a dozen ICQ clients alone), it is an overview of some of the best and most notable IM clients available today.
I connected, when supported, with users on AIM, Jabber, MSN, and Yahoo! servers for chatting and any other basic functionality that the client claimed. To all the developers' credits, I rarely found a feature claim that their clients didn't back up to at least a usable level.
That said, most of these programs are still in beta, and you will run into glitches. None of these blemishes ever got in the way of using the clients for their main purpose, but if you push their limits, don't be surprised if you run into some oddities. None of them, however, were so bad that simply closing and reopening the client didn't repair the problem of the moment.
Another thing to keep in mind is that if you expect these text messaging clients to also work as videophones (as their Windows cousins do), you're in for a disappointment. Yes, you can do text messaging. Yes, you can do file transfers with most of the clients. But if you want to see and hear grandma in Nebraska, none of these clients are able to do that job as well as the Windows clients. For my tastes, that's not a problem. If I want to do video-conferencing, I want a real video-conferencing program, not an overloaded IM client. Your viewage may vary.
If you want it, you can have AIM running on your Linux workstation today. You might not want to, though. The latest Linux edition dates from August 2001 and is several iterations behind its Windows big brother. Last spring and summer, AOL was taking AIM on Linux seriously. Today is a different story. While no one at AOL would come right out and say the project is dead, it's pushing up posies.
Still, once installed, with a modified GTK library, it does give you all the AIM basics, and if that's all you need, it's all you need. It should run on most Linux desktops of July 2001 or later vintage.
You may not want bother with AIM for Linux, though, because Gaim out-performs it. This Open Source IM client works with AIM, ICQ, Jabber, MSN, Yahoo! Messenger, and more IM systems than any of the others. If you want one client to talk to everyone, Gaim is it.
The newest version, despite its beta number, is much more stable than previous versions and is now as steady as any IM client I've encountered. While Gaim is meant for GNOME, you can run it flawlessly with KDE with the appropriate tweaks.
It's not as feature-packed or as pretty as Trillian on Windows or Epicware's Open Source Fire.app on Mac OS X, but another point in Gaim's favor is that you can add to its utility with plugins like a spelling checker or an RC5 encryption system. You can only encrypt sessions between Gaim clients, but more and more business users want that kind of protection, and relatively few clients deliver it today.
Everybuddy is another Open Source project that tries to talk to all major IM systems and it does a pretty fair job of it. While not as full-featured as Gaim and slightly rougher around the edges, it's a fine program in its own right.
Transferring files over it can be daunting, with some uploads and downloads unsupported. For example, the site says you can download files from your MSN friends, but, in the current RPM, you can't. That feature is still being tested.
On the other hand, Everybuddy does have a few interesting features that, to the best of my knowledge, are all its own. For example, you can use a filter with it so that you can try to talk to someone in another language using AltaVista's Babelfish as your translator. Thanks to Babelfish, this is more amusing than useful, but it does show that the developers have an eye to the future of IM.
Gabber is a GNOME-based IM client for the Jabber family of Open Source, XML-based IM programs. Jabber is the most popular IM service after the corporate threesome of AOL, Microsoft, and Yahoo!. You can use gateway programs with it to talk to AIM, MSN, and Yahoo! users, with the usual proviso that these may not always work.
Gabber, unlike Gaim, is much more picky about running in GNOME than KDE. While I was finally successful in getting it to run in KDE, more casual users should be running GNOME if they want to use Gabber. That said, once up, Gabber ran fine, although I did run into some odd crashes. Still, Gabber is a young program and shows promise, especially with its very attractive user interface.
Kinkatta is a pure AOL IM client without the other IM service trimmings. It is a solid, reliable client.
A labor of love by chief developer Benjamin Meyer, Kinkatta has a few features that other clients don't have, including the ability to print directly from the chat window and some advanced message logging features.
The ICQ for Linux site declares that Licq is the best ICQ client around. Who am I to argue? I've tried the others, too, and if I had to have one client and it had to be just for ICQ, Licq is the one I'd pick.
Why? Well, not to put too fine a point on it, but the program just shows that more elbow grease has been applied to its look, functionality, and speed than most of the other ICQ clients. Specifically, I like the skin support, the file transfer mechanism, the user search capacity, and on and on. If you want an ICQ feature and it's not in Licq, it may not be worth the having.
One of the major IM companies, Yahoo!, is taking Linux IM seriously. Its neat Linux client, while not as fancy as its Windows clients, includes such bells and whistles as access to user profiles, stock reports, and email access.
Of course, using the Web and HTTP for this instead of packing it all into an IM protocol helps a lot. The program is, however, optimized for Netscape. If you use Konqueror or another browser, you may have to do some tweaking to get Yahoo! Messenger and the browser to work well together.
Yahoo!, unlike AOL, is updating its Linux client on a regular basis. The latest build is from this summer, and I'm told newer versions will be out shortly. Alas, it's not Open Source. Despite that, YM actually has the widest OS support of all these programs. In addition to its Linux builds, YM also comes in versions for SunOS and FreeBSD.
YM is also limited in that it only works with Yahoo!. The good news about this, though, is that YM will still be working come the day that the more universal IM clients are having fits with the major IM services.
Again, it really depends on what services your friends are on. For ICQ fans, Licq is the one to beat. For personal use, though, and as someone with friends and coworkers on all the IM networks, Gaim is my favorite.
If you want a business IM client that works with the outside world, YM deserves your careful attention because, unlike AIM- and MSN-dependent clients, it's the most likely to work today and tomorrow.
You should also think about Gabber because Jabber seems posed to become a major, open IM server force in its own right. Its other advantage is that if you want an internal business IM system, you can simply install a Jabber server, and, with the right firewall settings, you can have your own internal Open Source IM system for a minimal investment.
Gaim's one big problem, along with all the universal clients, is that the major IM server companies, AOL (which owns both AIM and ICQ), Microsoft, and Yahoo!, have no reason to want unauthorized clients to use their systems. Worse still, they have several good reasons to block IM programs like Gaim, Everybuddy, and Kinkatta from their servers: advertising revenue from their proprietary clients, traffic on the last mile to their servers, perceived security holes, and cross-licensing deals with other software vendors, such as AOL enabling Lotus to use AIM servers with Lotus's Sametime client.
Because of this, AOL and Microsoft have both blocked access to their servers from non-authorized clients at times. While users want interoperability, IM companies aren't interested in supporting clients that don't contribute to their bottom line.
Currently, message protocol changes are used to block unwanted clients. AOL, for example, uses two protocols for AIM. OSCAR is the proprietary protocol, and there is no published specification for it. IM clients that use OSCAR, like Gaim, can find themselves blocked from the service if AOL fiddles with the protocol. So far, the free IM client programmers have been successful in reverse engineering these changes so that new versions of their clients will work with AIM again. TOC, on the other hand, is a simpler, well-documented Java protocol that AOL uses in its Java-based "Quickbuddy" AIM client, so many free AIM clients, like Everybuddy, use TOC.
The bad news for TOC developers is that AOL hasn't worked on TOC for some time, and it's not nearly as functional as OSCAR. For example, a TOC-based client can't support buddy icons or voice. On the other hand, AOL hasn't shown any signs of blocking access to its AIM servers with TOC, while OSCAR is changed fairly often.
While open protocols like Jabber and Simple (which is likely to be adopted by AOL and Microsoft) offer a way out of this programming problem, it's not likely to stop IM service providers from eventually blocking non-authorized IM clients using server-based authorization schemes, like Microsoft Password and Project Liberty, which is supported by AOL.
This review was adapted from a NewsForge article which only discusses GUI IM clients, so I want to put in a word for some of the more popular console clients.
The Unix console, of course, is where realtime Internet communication began, and you'll find talk/ytalk/etc. in most *nix distributions if you need it to talk to someone or if you and a friend just want to feel retro.
The more mainstream console IM clients, like the GUI clients, are divided between those that are made to connect to one IM system and those that work with several.
mICQ is the grand-daddy of console ICQ clients. It still has the same minimalist look and IRC-like interface that it had when I used it years ago, but has developed a respectable feature set over the years. If you want simple ICQ access, it may be for you.
naim is a wonderful AIM client with a unique and easy-to-use interface. Since it uses TOC, it's continued to work while other clients have scrambled to catch up to protocol changes. If you want a simple, stable AIM client, naim is it.
The traditional choice for dedicated Yahoo! chatting on the console is Ari's Yahoo Client. Unfortunately, it's recently become a victim of Yahoo!'s ceasing to support clients based on older versions of Messenger. Until that's worked out, you may want to try your luck with the newer gnuyahoo.
IMHO, the greatest of all console IM clients is the multi-protocol centericq.
I've sometimes wondered why a good console Jabber client has never appeared. The only one that's even worked for me is IMCom, which is rather primitive. I was using Everybuddy when I first heard about Jabber, and I expected a console Jabber client to appear quickly; I thought it would be a common geek itch waiting to be scratched. Unfortunately, nothing surfaced, and when I cut back on my use of GUI applications, I ended up with three screen windows devoted to IM clients.
centericq, despite what the name implies, came to my rescue at last, not as a Jabber client, but as the child of someone who was willing to add support for many protocols on his own. centericq now boasts support for ICQ, Yahoo!, MSN, AIM, and IRC, and has an excellent interface and a huge number of features and configuration options. The centericq mailing list is lively, and development is continuous. No matter which IM service(s) you use, give centericq a try.