The notion of social networks as open platforms are going take a big step forward this week when Google officially announces OpenSocial, a set of common APIs to let developers create applications that run across any OpenSocial compatible site. The APIs will cover many of the essential social networking functions: Profile Information (user data), Friends Information (social graph), and Activities (things that happen).
As first reported on TechCrunch, on Thursday this week Google will unveil details on the initiative along with their launch partners. On the social network side they will be joined by sites supporting the API including Salesforce, Friendster, hi5, LinkedIn, Plaxo, Newsgator and Ning (with Google's own Orkut included as well). On the application developer side they will be joined by some of the leading Facebook developers including Flikster, Rock You, Slide, and iLike.
It is interesting that this is not a social network but a compatibility layer across networks. This has the potential to make developers lives easier while at the same time giving Google and Facebook's competitors a means to dent Facebook's current momentum.