I flagged a question on ELU as proofreading, (which it is). I see later that it has been put on hold, but only by Dan Bron and tchrist♦.
How do flags work? I'm not trying to get a mention or any rep (not even sure if that happens), I'm just curious as to what would make an asker's flag be regarded as useful. Is it because I flagged the question under a different category, or don't I have enough reputation?