I built a poc for something like this using github data, but it didn't really go anywhere. <a href="http://getvouched.com" rel="nofollow">http://getvouched.com</a> and <a href="http://getvouched.com/visualizations" rel="nofollow">http://getvouched.com/visualizations</a>
Isn't the "search for developers by GitHub profile" what GitHire.com was doing? And then they realized that it was "too hard" to find devs in the SF Bay Area, where they're in high demand?