OpenSocial really only requires that the function exist. If you try
to call the function, Friend Connect gives you back a not implemented
error code as per the specification. This is the correct behavior for
implementations that don't support messaging through the API.
-Bob
Short answer is that I don't know. We have a messaging system now,
but exposing it to the API would require quite a bit of
security-related work. We wouldn't want to expose it through the API
in such a way that spammers could use it to send messages to any GFC
ID or any member of the community. So for all intents and purposes,
there is no ETA on this feature.
-Bob