What it tells you about the candidate pool may be less than what it tells you about the qualifications for the position. Job requirements in the computer industry routinely include nonsensical requirements (5 years experience in something that's been around 3 years, 2 years experience in each of 8 items for an entry level position, etc.)

This is endemic to the point where applying only for jobs where you fit the job description is a losing strategy.

And even if your own job posting isn't one of those, how is the applicant supposed to know you're one of the few employers who actually means what's in the job description?