My company is making a business of identifying great developers (gild.com). It is a notoriously difficult task, even with the wealth of information developers tend to make public about themselves.
That sounds like a fantastic way to find scads of mediocre developers. Development isn't about language, it's about comprehension.
I guess I'm gonna be a negative Nancy here, but I know some very good developers that don't make anything about themselves public. I expect some of the very best are completely invisible on the internet, at least by their real name, because they're too busy working on things their employers would rather keep as trade secrets.