[taliesinb]

One of the thing that we (Wolfram) have noticed is that our NKS summer schools provide a great way to track someone's problem solving ability (and domain expertise) over a long period. A lot of previous hires for Wolfram|Alpha have come from summer schools. The Cambridge grad who wrote Alpha's first-generation parser, for example, studied at the very first summer school in 2003.

Two related things: we get a lot of international applicants, and this turns out to be a great filter for selecting very motivated and talented people who have perhaps saturated the opportunities their local countries can provide them (certainly this was true of me for South Africa).

Another thing is that the math and physics people who apply seem to adapt better to programming in our house functional language, Mathematica, than people with a more traditional CS background (MIT's SICP aside, do they still do that?).