I would have made it Silicon Valley only: either you live there, or you'll move there. (I'm in New York, so it might seem unusual that I'm suggesting excluding my city, but you need to limit inflow and that's the best way to do it, because job markets are pretty local. You add cities once you have traction and are looking to scale.)
Then I would have partnered with a company like Kaggle in order to get access to people who can actually code. I've met a lot of mediocrities with prestigious resumes. One of the biggest problems with hiring is the number of people who have established a great connections <-> great jobs loop but don't know anything.
They focused on the right thing. The target audience isn't the startup that cares about getting the best people, just the ones with the best pedigrees. This would be perfect in finance.
Sure, an excellent engineer employed at $200K with a vast network is unlikely to send his resume to Craigslist ads, but they may use a simple way to find out whether they could get $300K and a $500K signing bonus.