Depends on the economy, I would guess. I haven't had to do a lot of hiring recently, but a couple years ago at my last company we found ourselves overwhelmed with applicants to PHP programming jobs. We created an application tool that asked applicants to solve a few PHP puzzles. These weren't super-hard MIT-level questions, just basic FizzBuzz. We found it to be a very effective screening process.

This probably works best for entry level/junior programmers responding to a help wanted ad. Senior people are being proactively recruited.