We've started using [http://wiki.opensocial.org wiki.opensocial.org] for all !OpenSocial content.  On that site you'll find
 * An editable API reference with code samples
 * A list of containers with sandboxes or live deployments of !OpenSocial
 * !OpenSocial spec changes
 * Articles and tutorials
 * Lots of other resources


[http://code.google.com/p/opensocial-resources/w/list List of old pages on this site]