I talked to them before releasing something to the public. I'll share their response here:

"Hi Christoph,

Thanks for taking the time to ask.

I don't see a problem with this, as it's data that anyone could easily mine out of the public database dumps that we release. The Careers 2.0 candidate search is an entirely different thing, and goes way beyond being able to show you developers from (area) that might know something about (technology).

When we used to facilitate (and later switched to just encouraging) periodic world-wide meetups with fellow Stack Exchange users in your area, Our SEDE and DB dumps were what people used to see if there might be an interest in any given area. Given that we don't facilitate any way for users to be contacted through the site unless they make their contact information available on their profile, I don't think this would annoy anyone at all.

Not required, but I'd love to take a look at what you've built once you have it ready and somewhere public :) Nothing official, I'm just curious.

Regards, - Stack Exchange Team"