I was clicking in the "Help us Grow this Site" box on the Pro Webmasters beta site, and there's a couple things that caught my notice.
First off, when focusing on the various icons, the layout shifts in a nasty way (FF 3.6.6):
Secondly, I question the choice of text for the pre-populated facebook link description:
Pro Web Masters is a collaboratively edited question and answer site for professional web masters. It's 100% free, no registration required.
"100% free" for me is a mental trigger for suspicious or misleading behavior on the web. I would just say "It's free to participate" or something along those lines.
IMHO, I would also argue that "webmasters" and "web masters" have entirely different contexts, and it should say "webmasters" in both cases.