"In fact, Pidgin supports no less than 17 different IM
protocols! As well as the four popular ones I mentioned above --
MSN, ICQ, Yahoo and AIM -- there is Bonjour, Facebook Chat,
Gadu-Gadu, Google Talk, Groupwise, IRC, MySpaceIM, QQ, SILC,
SIMPLE, Sametime, XMPP and Zephyr.
"Some of these are found in the corporate world -- for instance,
Sametime is a component of the Lotus Domino suite. Similarly,
Groupwise is also an enterprise offering."