I think this would be great for fostering local community. I mean not everybody can go to Dev Days ya know?
Because - and pay close attention here, because it's not terribly obvious and a lot of people make this mistake - because, Stack Overflow is not Facebook.
It could be, of course. Don't think for a minute that Atwood & Co. aren't perfectly capable of writing Facebook. But why would they opt for fame and untold riches, when they could instead provide a narrowly-scoped Q&A site for programmers?