I've heard somewhere (possibly from Joel himself, to be fair) that it typically costs a company around half a year's salary to hire an employee (between recruiting costs, etc.) $500/week is a drop in a very large bucket for most employers - at least the kind that are doing active recruiting. They're probably spending way more than that just in personnel time to review resumes - and in fact, being able to filter a bit better by quality will save them that much more in the screener's time.