Especially at a company like Zynga, that at least as far as I know, had a fairly rigorous interview process. It's a chance to get a pre-screened engineer, possibly on the cheap.
understandably a company would want to pay less for higher quality work, but at the same time if the process was rigorous and assuming many tech recruiters are also trying to poach the employees - i would think 'on the cheap' wouldn't really apply given supply/demand here
It is on the cheap in the sense that they wouldn't expect to screen such people as much. It obviously isn't free, costs more than hiring from within, but cheaper versus trying to gauge recent graduates and the like.
