There would seem to be a pretty narrow range of companies that this would actually work for.

If you're a pet food manufacturer that needs a website, you're probably not going to find anybody who's really stoked about catfood and also knows Rails.

If you're Valve, you'll have no problem finding 10,000 kids who really want to write video games, none of which can code their way out of a sack.

So it would seem to follow that if you're looking to hire developers, you should start off by looking for people who are actually good at writing code. Or put another way, by looking at credentials.

It'd be cool if it worked the way the author describes, but for most situations I just don't see it happening.