So it's kind of like the instant message on FB.
I think this forum is fine as is. No need for IM.
We already have the PM option for person to person comments.
The biggest issue with an open IM setup, is that most sites are required to monitor IM.
FB monitors all IM, even if it's only between 2 people, for the sake of "Cyber-Bullying" and for talk of "Illegal Activities".
So if you use IM on FB, someone else HAS read ALL of your private IM's!
Just another way for Big Brother to keep an eye on things.
Skad does a great job of letting this be a truly open forum, and for the most part, allows us to self police ourselves. No need to put more work in his lap!