Gaim is a multi-protocol instant messaging (IM) client for Linux, BSD, MacOS X, and Windows. It is compatible with AIM and ICQ (Oscar protocol), MSN Messenger, Yahoo!, IRC, Jabber, Gadu-Gadu, SILC, GroupWise Messenger, and Zephyr networks.

Gaim 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.

Gaim supports many features of the various networks, such as file transfer, 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, spell checking, tabbed conversations, and more.

Gaim runs on a number of platforms, including Windows, Linux, and Qtopia (Sharp Zaurus and iPaq).

Gaim integrates well with GNOME 2 and KDE 3.1's system tray, as well as Windows's own system tray. This allows you to work with Gaim without requiring the buddy list window to be up at all times.

Gaim is under constant development, and releases are usually frequent. The latest news regarding Gaim can be found on the news page.

Trillian is a fully featured, stand-alone, skinnable chat client that supports AIM, ICQ, MSN, Yahoo Messenger, and IRC. It provides capabilities not possible with original network clients, while supporting standard features such as audio chat, file transfers, group chats, chat rooms, buddy icons, multiple simultaneous connections to the same network, server-side contact importing, typing notification, direct connection (AIM), proxy support, encrypted messaging (AIM/ICQ), SMS support, and privacy settings.

Without stealing your home page and with no other included software, pop-ups, or spyware, Trillian provides unique functionality such as contact message history, a powerful skinning language, tabbed messaging, global status changes (set all networks away at once), Instant Lookup (automatic Wikipedia integration), contact alerts, an advanced automation system to trigger events based on anything happening in the client, docking, hundreds of emoticons, emotisounds, shell extensions for file transfers, and systray notifications.

Version 3.1 adds a new identity feature that helps you organize your home and work contact lists, HTML editing for AIM profiles, UPnP support, enhanced IRC performance, and speed enhancements.