Google and Microsoft have long been rivals, especially with Microsoft trying to develop its online divisions more. Microsoft recently took a $240 million stake in the popular social networking platform Facebook. Google on the other hand countered this move by creating a set of APIs through its new OpenSocial platform. Google also signed on some key players such as MySpace and Bebo to the OpenSocial platform.
Personally I think the Google move was vastly over hyped. There are many platforms on the web today that have adopted open APIs with much less of a commotion. I think that Microsoft's investment will win this round of the hotly contested social web space.
