Have a look at dating sites, there's much more innovation going on in that space, and they're essentially having to deal with exactly the same matching problem.

Have a look at dating sites, there's much more innovation going on in that space, and they're essentially having to deal with exactly the same matching problem. However one of the big issues with innovating in this space is that HR departments are generally quite conservative so it's hard to sell innovative products to them (look at the difficulty SnapTalent had with their initial product). You'll probably have more luck selling to third party recruiters who are more risk tolerant. There's about a dozen companies currently doing the whole social network recruiting thing, but none of them has serious traction, and I'm not personally convinced it's a model that will work. I'm working on this problem by building a niche job site, it's not hugely innovative technically, but it should help with the relevance problem and also be traditional enough to appeal to HR departments. One of the other ideas I had in this space was building a platform for matching recruiters to candidates, so recruiters could send targeted messages to candidates matching a set criteria (+using game mechanic techniques to stop spamming). If you want to talk more about this idea feel free to drop me a message.