Online status indicator. On forum posts and user comments, and on the userlists for projects (and the general userlist) create an indicator of some sort that shows that a user has accessed the site within the last 10 minutes. Allow users to "Hide online status" in their user profile edit page. FIXED: in userlists and comments and forum posts, you can see the online/offline status. A user is "online" if he's accessed the site within the last 10 minutes. It's the best I can do without establishing winsock connections and polling, like Yahoo IM does. I don't think online accuracy is as important here, so this will do well enough.