Sametime
Sametime was developed by IBM as a business instant messenger that integrates with Lotus Notes and third party software such as Microsoft Office. Though it is a closed protocol it offers support for communications standards and standard protocols, including Session Initiation Protocol (SIP), SIMPLE, T.120, XMPP, and H.323. One of the features is IBM Lotus Sametime Gateway, which adds support for communication with users of AOL, Yahoo, Google Talk and various XMPP based Jabber communities.