It's been a busy few days. The OpenSocial Foundation sprang into being on Tuesday, with MySpace, Yahoo!, Google, and Hi5 as initial members; on the same day, Microsoft announced contact portability for its Windows Live Contacts service, partnering with Facebook, Bebo, Hi5, Tagged, and LinkedIn to access and re-use contact data. (We announced the Google Data Contacts API on March 5.) Seems like there's a trend here!
On a somewhat related note, we're moving forward on the OpenSocial RESTful API.
Update 3/31: Hi5 too!