I don't think there is a character limit. That may be an issue.
Also, I want to be able to hotlink. I want to post image and video links without uploading.
Also, I want a notification system other than email to let me know when someone mentions me.
Also, I want ways to sort my friends, and stuff.
Also, I want an event system or some broader temporary/temporal node thingy for connecting some folks.
Also, I want an enchilada or dumplings for lunch.