Pidgin

Pidgin, formerly called gaim, is a multi-protocol instant messaging client that is compatible with AIM and ICQ (both of which use the Oscar protocol), the old AIM protocol TOC, MSN Messenger, Napster (deprecated since the demise of Napster, but still included for use with the OpenNap project), Yahoo, IRC, SILC, Novell Groupwise, Jabber, Gadu-Gadu, and Zephyr networks.

It supports many features of the various networks, such as file transfer, buddy icons, away messages, typing notification, and MSN window closing notification. It also goes beyond that and provides many unique features. Some of the more popular features include:
 * Buddy Pounces - send a message, play a sound, pop up a notification, or run a program when a specific buddy goes away, signs online, or returns from idle
 * Plugins, including text replacement, a buddy ticker (like a stock ticker), extended message notification, iconify on away, encryption, and more.
 * ALL the extra features of DeadAIM and AIM+ for Windows, excepting "MSN style popup notifications" (available as a plugin), "Automatic logging of images and sounds", and window transparency effects for Linux (the Windows port supports transparency).

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