Yesterday Google announced OpenSocial, and the social media landscape changed dramatically. OpenSocial is a set of common interfaces for developers to build applications that work across (almost!) all the major social networks, like MySpace, Friendster, Hi5, and so on.

Noticeably absent from the launch day announcement is Facebook, which until yesterday had the monopoly in the world of social network applications. Over 7000 applications have been developed on Facebook in the 5 months since they announced the developer platform. Anyway you cut it, 7000 applications developed to target your 50M users is an impressive achievement.