So far, for me, it's been the lack of response either way. I shoot my resume out in to the void for nothing to ever come back. I don't know if my stuff didn't go through, or it's a no. I'd rather get rejected than get nothing back.
Also the line "We'll keep you in mind if there's an opening we think you'd be a good fit for". I highly doubt any of these people are like "We need a new _______ lets go through all these rejected resumes and see if any fit". They're just going to slap the new posting up and sift through the new responses, so why lie about it?
Oh I hate the "We'll keep you in mind..." stuff. That's a polite way of saying your resume is going in the reject pile but thanks for giving it to us.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.