As long as you can also turn it off, a chat feature would be cool. I sometimes get annoyed with the frivolous messages sent to me, I'd go insane if too many people attempted to chat with me at the same time, lol. Unfortunately though, it'll be mostly men speaking to other men posing as women.
Another nice feature would be spell check. I know it's WAY LESS cooler than a chat feature, but some of the spelling and grammar is alarming. I'm not referring to international members.