I've been on the site a small while - and i see the Community user bumping questions some of which , maybe even all of them, probably need to be closed/answered/something so that they don't get bumped again. I understand its community or "crowd sourced" and should eventually happen - but I'm a little unsure how it happens and if I can contribute - is it rep based, vote based or too hard?

Is there a method for someone other than the original poster to say a question is answered? I see this feature used on the Microsoft sites - really really badly - so I would understand that this site will never do that - Is there any description of how old questions decay and get deleted

I see questions which are well "old" , but get bumped some have correct answers (IMHO so I get that maybe I'm wrong)- but none marked as answers and I have a feeling that bumping these with no method of saying its complete - is wasteful or could be tuned better