At the Fall 2011 EREExpo I had a chance to walk the exhibit floor for product demonstrations. I asked for a demo that would highlight the things that make the product unique. Here is what I learned about Careers 2.0:

If you are in IT recruiting you are probably already familiar with Stack Overflow, the Q&A site for programmers. It is a community of over 400,000 people who ask and answer about 2 million technical questions a week.

They have built a job board and candidate search capability around this community. The big kicker here is that you don't just get a resume on a person, you get to see the questions they have asked or answered in Stack Overflow, and can even search based on that content.