HelloJS is a client-side Javascript SDK for authenticating with OAuth2 (and OAuth1 with a oauth proxy) web services and querying their REST API's.
HelloJS Standardizes paths and responses to common API's like Google Data Services, Facebook Graph and Windows Live Connect. Its modular so that list is growing. No more spaghetti code!
HelloJS supports a lot more actions than just getting the users profile. Like, matching users with a users social friends list, sharing events with the users social streams, accessing and playing around with a users photos.