The world of instant messaging is crowded and becoming even more so. It began with ICQ (does anybody use it today?), which was closely followed by AIM, MSN Messenger, and Yahoo Messenger . More recently, this trio is being challenged by other IM chat protocols, like Google Talk, and even by social networks like MySpace and Facebook , which have their own instant messaging features.
What this all adds up to is ... a huge mess. To use any of these IM services in their native formats, you have to download and install a different chat program.
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That's where instant messaging applications like Digsby, Pidgin, or Trillian come in. These chat apps -- which can be described as cross-platform or multiprotocol IM apps -- support more than one instant messaging network. Instead of having the AIM and Yahoo Messenger chat programs running on your computer at the same time, you can use just one application to access your accounts from these two IM networks.
All of these multiprotocol IMs have been developed independently, most without the official support of any of the companies that own the IM networks. Perhaps as a result, the eight multiprotocol IM services covered here are very different from one another in terms of functionality and user interface experience.
In addition, these are all free apps -- at least, for individuals. A couple have "pro" or enterprise-level versions, in which case the free version is a good way to test it out first.
Note that almost none of these multiprotocol IMs (with the exception of Trillian) support the webcam/video chat functionality of the major IM networks (which include AOL , Yahoo, and Microsoft). The companies behind these IM networks keep their video chat technologies proprietary, so it's a challenge for the developers of unofficial, third-party IM clients to reverse-engineer this feature.
What follows is a quick (and opinionated) rundown of eight of these instant messaging applications. In the end, which one you will want to use depends on how you feel about using an instant messaging system, and what you use it for.
The quick rundown: Until recently (when VoxOx appeared), this was the sole multiprotocol instant messaging choice for Mac users. Like Pidgin and Miranda, Adium is open source. But, just as Miranda is only for Windows, Adium is exclusive to OS X. Along with the most popular IM protocols, Adium supports messaging through Apple's MobileMe service and Bonjour network technology.
Quality of user interface: Of course, being a Mac-only application, Adium was designed by its developers from the start to mesh with OS X. The buddy list and chat windows of Adium fit right in with the standard OS X scheme, yet its layout will be familiar to anyone who uses an IM app on another operating system platform.