Meebo supports multiple IM services, including Yahoo! Messenger, Windows Live Messenger ,AIM, ICQ, MySpaceIM, Facebook Chat,Google Talk and others .
Meebo bar allows users to connect with their friends and share content on hundreds of content sites across the web including TV Guide, Slate, TMZ, CafeMom, Entertainment Weekly and others.
Meebo reaches over 190 million unique users globally .
The "meebo me" widget gives bloggers and webmasters a way to add chat using meebo to their sites.
Meebo group chat rooms allow group chat as well as the ability to post media like pictures, video, and audio.
Trillian
Trillian is a proprietary multiprotocol instant messaging application for Windows, Mac OS X, iPhone OS, BlackBerry, Android, and the Web, created by Cerulean Studios.
It can connect to multiple IM services, such as AIM, ICQ, Windows Live Messenger, Yahoo! Messenger, IRC, Novell GroupWise Messenger, Bonjour, XMPP, and Skype networks as well as Social Networks, such as Facebook, Twitter and MySpace; and email services, such as POP3, IMAP, Gmail, Hotmail and Yahoo! Mail .
Trillian will automatically shorten URLs in your tweets, and handle direct messages, re-tweets, and replies.
There's support for drag-and-drop file transferring .
You can preview a Web site when you hover the cursor over a URL in the conversation window
BeeJive
BeeJive is an extremely popular Instant Messenger app for the iPhone .
It’s a premium app that combines gorgeous visuals with an intuitive user interface .
BeeJive IM supports multiple IM services, including AIM, Google Chat, Facebook chat and many others.
It lists your chat sessions in a column on the right side of the screen.
Rather than require a friend to accept a file transfer, BeeJive sends multimedia in the form of a URL for the recipient to view on a webpage.
Cost:$9.99
BlackBerry Messenger
BlackBerry Messenger (BBM) is a proprietary Instant Messaging application included on BlackBerry devices.
It was developed by Research In Motion (RIM) .
Messages sent via Blackberry Messenger are sent over the BlackBerry PIN system , thus, communication is only possible between two BlackBerry devices.
With the release of BlackBerry Messenger 5.0, BlackBerry allows users to use a QR Code barcode to add each other to their respective friends lists rather than using only numeric PIN identification
