Trillian

Empathy is a messaging program which supports text, voice, and video chat and file transfers over many different protocols. You can tell it about your accounts on all those services …

Spark is an Open Source, cross-platform IM client optimized for businesses and organizations. It features built-in support for group chat, telephony integration, and strong security. It also offers a great...

Digsby is a multiprotocol IM client that lets you chat with all your friends on AIM, MSN, Yahoo, ICQ, Google Talk, and Jabber with one simple to manage buddy list. …

iChat (formerly iChat AV) is an AOL Instant Messenger (AIM), MobileMe, ICQ and XMPP client by Apple Inc. for their Mac OS X operating system. Using a Jabber-like protocol and …

Subway is a web-based IRC client with a multi-user backend and a JavaScript-heavy UI. Frontend/backend communication is done with websockets (or best available fallback where not available). The backend...

Meebo is integrated, all-in-one instant messaging (IM client) that connects you with your friends everywhere. It supports a large number of popular servicesand connects you to MSN, Yahoo, AOL/AIM, MySpace, …

Zen Talk is a web-based application for instant messaging. -1267 times lighter than Facebook. -319 times lighter than Facebook Mobile. -686 times lighter than Meebo. -Lightning-fast chat. -No adds. -Save …

Meebo for the Desktop. It uses Adobe® AIR™ to place meebo home page on the desktop in its own window.

Minbif aims to use the libpurple library from the Pidgin project to provide an IRC-friendly instant messaging client.