if you’ve actually had an interview (on the phone or in person) then the recruiter should get back to you to tell you that the position has been filled, or canceled, or whatever. I’m going to say it now and let the recruiters come attack me: There is no reason short of death (of the recruiter) that justifies not getting back to a candidate. It’s just plain rude and unprofessional. Plus, you may not need that particular candidate now, but you might need him later.