Pidgin is a multi-protocol instant messaging client. It is compatible with
Oscar and TOC protocols, ICQ, IRC, Jabber, Gadu-Gadu, and Zephyr networks.

Pidgin users can log in to multiple accounts on multiple IM networks
simultaneously. This means that you can be chatting with friends on AOL
Instant Messenger, talking to a friend on Yahoo Messenger, and sitting in an
IRC channel all at the same time.

Pidgin supports many features of the various networks, such as file transfer
(coming soon), away messages, typing notification, and MSN window closing
notification. It also goes beyond that and provides many unique features. A
few popular features are Buddy Pounces, which give the ability to notify you,
send a message, play a sound, or run a program when a specific buddy goes away,
signs online, or returns from idle; and plugins, consisting of text
replacement, a buddy ticker, extended message notification, iconify on away,
and more.

(Adapted from the About Pidgin page.)

Libgaim is a backend library and protocol modules needed for Pidgin frontend
frontends such as the GTK+ and console UIs.