Microsoft has finally announced interoperability between Windows Live Messenger (the next version of MSN Messenger) and Yahoo Messenger. The two platforms have a combined total of 350 million users, and the deal has created the world's largest consumer-facing IM community. During the limited public beta, users can exchange instant messages, see their friends' presence status, share emoticons and add friends to either service.
This is a great move that marks a wider trend towards opening up social services. AOL's AIMPages, for example, integrates with many of its competitors, while open APIs have been a big part of the Web 2.0 success stories - Flickr, del.icio.us, Google Maps. However, companies tend to open up for one of two reasons: because they're the underdog, or because they feel threatened by other players in the market. It would be nice to think that Microsoft and Yahoo are putting the user first, but it seems unlikely.