I kinda think it'd be interesting to see.
Pros that I can see with it are..
Improved networking and communication with friends
See people you haven't seen for awhile (too similar to facebook, I know)
Cons..
I'd prefer to steer clear of facebook, but I'm sure this feature isn't/couldn't be strictly associated with networking sites and wouldn't really be a noticeable change.
I'm sure other forums, not just networking sites, have a similar feature.
I really don't see any harm in it, though that's really about all I can think it has going for it. Withholding my vote for now.