Hooked on Jabber
I know a bunch of people who use ICQ to cover their Instant Messenging needs. I know even more who use Microsofts Messenger. As if that wasn't enough a few people have opted to use Yahoo! Messenger.
I have been using Trillian to satisfy my imaginary need for being present on 3 IM systems at the same time. Trillian does a fine job of this and is definatly a better choice than having 3 IMs running.
Jabber isn't an instant messenger like Microsoft Messenger or Trillian is. Jabber is an underlying protocol and a general framework for Instant Messenging. It is based on solid and openly defined standards like XML, PGP and HTTP. For this very reason there is a multitude of Jabber clients for several different platforms.
All of these clients can naturally communicate with eachother via the Jabber network (consisting of free servers around the world), but more importantly, they can communicate seamlessly with the IMs I mentioned above.
While Trillian handles multiple IMs by connecting to each network on its own, Jabbers legacy support exists serverside. As long as the Jabber server has the proper transport filters installed you will be able to communicate with your friends - and they'll never know or have to know that you're not using ie the ICQ- or the MSN client.
From an end-user point of view, this is a great way to go about it. You don't have to do a thing to use your existing IM accounts from all Jabber Clients. Neither will you have to do anything if Jabber decides to add transport for yet another IM system, your client will automagically know how to use it when your Jabber server is upgraded.
From a developer standpoint it is just as good. If you want to create an application that sends or receives messages via MSN, you simply create the application using the Jabber specifications (which are publicly available unlike any of the other systems). Voila, you application is able to communicate with ICQ and AIM too. And with the specifications being public you can get as nitty gritty on the lowest level as you want, or you can settle for one of many higher level Jabber libraries already created.
Jabber has definatly made my daily Instant Messenging a lot easier. Add the fact that with Jabber I have several free clients available to me, and the result is obvious: I am hooked on Jabber.