So, I'm not part of a FC yet and can't comment on those.

However, as part of the normal user interface, I've noticed a few things that seem to be lacking for social interaction.

Specifically with regards to notifications: there's the option for a noise when you get a /tell, but nothing for LS chat. There's also no notification when a friend signs on or anyone in the LS signs in (or out). I don't think these should be forced, mind you, but having the option to be notified (just like with /tells) would be nice, especially as the general chat box gets very crowded very fast if you're doing something like synthing (I created a separate "chat" "tab", but even that can move quickly).