We don't think number of tweets or followers is a relevant means of assessment at all—quite the opposite. Ashton Kutcher is not an interesting candidate for a rails job, and that should be reflected in our report for him (were he ever to apply for such a position.)
We obviously gather a lot of metrics (hey, storage is cheap) but the ones we actually use in our scoring mix right now are tied to two simple concepts: does this person care about their craft, and do they enjoy any amount of professional respect for what they do.
We aren't offering shoe size; what you need in early-stage hiring decisions is an indicator: something more fast than perfect. Resumes suck at this because everybody is trained to write sterile, "professional" resumes stuffed to the brim with keywords. We can tell a much more interesting story—today!—with the kinds of data that most developers in our industry are already sharing. SO reputation isn't a story, it's a data point. What tech people ask questions about versus what tech they answer questions about reveals something more interesting. They know Python very well but seem to be exploring JavaScript? Interesting. Maybe a hybrid in the making.
Skills isn't for everyone and every industry; it's for one industry and a very specific breed of candidates that has this kind of publicly-visible track record. We think there are enough companies that are hiring in this space that there's a business to be built here now, and the Internet trends towards more public data. Do we really think that we'll still be using resumes in ten years to assess whether to spend more time on engineering candidate X?
