I prefer open standards
I use Jabber/XMPP for messaging. Some client programs you may have heard of:
Windows ---
• Pandion
• Exodus
• Gaim (now Pidgin, thanks to a lawsuit from AOL) (Multi-Protocol, AIM, Yahoo, MSN, etc...)
• Gajim
• Spark
• PSI
Linux ---
• Gajim
• Gaim (Pidgin) (Multi-Protocol, AIM, Yahoo, MSN, etc...)
• Spark
OS X ---
• Adium (Multi-Protocol, AIM, Yahoo, MSN, etc...)
• Proteus (Multi-Protocol, AIM, Yahoo, MSN, etc...)
• Spark
• PSI
And more that I can't remember.
Before the sites I'm running on my server started to consume too many system resources, I ran my own Jabber server.
Unfortunately, some people are still stuck in the ancient times and use AIM (hence the only reason I still have an AIM account, for those people).
