I built a similar service that starts with github data and lets you add whatever you want to it. It's more than just language skills you want to hire for.

It uses a nice visualization: http://getvouched.com/visualizations?id=maxdemarzi

Try putting a github username or use the drop down list on the page.

Ultimately you get this profile: http://getvouched.com/users/max/vouches

It uses pagerank + proximity, so if a developer who does have his stuff on github vouches for you, you get all that credit without having to use github.