Something that I personally would love to see out of this site is a desktop client, something reminiscent of AOL chat would be so interesting, and would fix my biggest issue with the site in general (and I don't think I'm alone in this) notifications.
because the site doesn't auto refresh, notifications will not appear on your homepage until you yourself refresh the page. Not a problem for friend requests or blog comments, but for IM's it means that I am not notified when someone messages me. this means keeping up with a conversation is super hard unless I just have it open on another window.
This is fixed on the app by having push notifications, and I think it can be fixed here with a desktop chat client, The ramifications of this I am not sure, but having a downloaded chat client that sends you a notification when someone has sent you a message would be an absolute gamechanger, at least to me.
alternatively, you could what twitter does, and just auto refresh your notifications every couple of seconds so you know when you have one.
alright, idea over thoughts?