I wouldn't use a chat system built in, besides a shoutbox. My point was integration into the profile where say I am signed into AIM, maybe an image pops up saying I am online or something. Same thing in the profile view, it should have an online image, or when someone is viewing a topic, like my posted comment above maybe a image says I am online. Maybe its added and I fail to see it :P
Edit: ok so we have that little orange guy that says we are online, what about in the profile?