I've been thinking about this a lot recently. You wouldn't believe the number of people (VCs, marketers, recruiters, etc.) who strongly have pushed for a similar system implemented in GitHub over the years. The entire concept of open source on GitHub would have basically been a front to become a LinkedIn of developers.

I don't mind sites like the one here coming along and attempting to do this (it has some value), but I'm really proud that GitHub didn't head in this direction, even though there was a fair amount of pressure towards it.