As read on Al Jazeera:
http://english.aljazeera.net/NR/exeres/37E73343-F013-4369-BFD5-A3DD294DDF71.htm

More information on:
http://developer.yahoo.com/messenger/

Yahoo opens up its messenger platform.
Mainly it's offering the ability to develop plugins. There are already more than 100 plugins available. E.g. event sharing (integrated with the map functionality), comparing calendars, etc.

But if I'm rightly informed it'll be also possible to hook in to the voice streams, etc.

The messenger war is going one step further again... Who will make which move when?