For grabbing contacts from Facebook I am experimenting with telepathy-gruschler right now:
http://cgit.freedesktop.org/~hasselm...athy-gruschler

Still Facebook can hardly be used to automatically annotate contacts with Avatars: The API is too closed. For instance it doesn't export any reliable information like email addresses or phone numbers for privacy reasons.

Gravatar support? Yes, this would make sense. It's an easy to use service.