I keep on seeing percentage of accept rates beneath account info showing at answers or questions. what I don't get is, what are they? what do they do?
Accept rate is the percentage of questions you've asked for which you've accepted answers. By accepting an answer (that check mark you only see when you are the question author), you let future searchers know that that answer was most helpful in solving your problem.
Accept rate is not displayed for users who have asked very few questions.
Accept rate does not include very recently asked questions (so you aren't penalized for waiting a couple of days to see if a better answer shows up).
Some users feel that their time is best spent answering questions for which the questioner is likely to accept an answer -- either because they want the chance at the reputation awarded when one's answer is marked "accepted", or because they want to help other visitors to this site find the right answer faster.
Accept rate is calculated and displayed by the site, but has no actual effect. It's just there for other users to see.