Although this is rather project specific and would not perhaps convey general skill level. It might be and idea to see how a developer is doing on StackExchange helping others and getting help. The combination of Codeivate and S/E could be gold mine of useful information. I think the tags could be inserted either automatically when my SE question is added or inserted by hand to explain what I am doing. They could look a bit similar to soundcloud tags.
Customer support service by UserEcho