Funny, as I think about the game I'll never make, I've been thinking about how best to do a hive based chat.

I've played a ton of the browser games people are making and built-in group chat makes them sooo much better. You are so often waiting on timers, or contemplating how to best use your last few actions, etc. that all the players have a lot of down time. If you have a chat window on the right side, so long as there are enough players that they occasionally run into eachother, the chat will be used and develop a community.