The latest example is My idea about finding the largest prime number where OP asks about a distributed processing approach to find prime numbers. There was a comment: mersenne.org – pedja which OP accepted in another comment as showing the idea was not original. There are no answers, but OP seems happy. If nothing more happens this question will continue to be bumped by the robot. Should there be a closure reason to deal with this? I think so.

• Peripheral note on "...bumped by the robot." I have never seen a question with 0 answers bumped by the robot. It seems only questions with at least one answer but none with positive score get bumped. Am I wrong? – Jonas Meyer May 5 '12 at 4:16
• @JonasMeyer: I believe I have seen questions with no answers bumped, but don't see an example on the front page right now. Certainly those with answers with no upvotes get bumped and I am prone to upvote an answer (even if I don't think it is very good) just to stop that. – Ross Millikan May 5 '12 at 4:19
• – Martin Sleziak May 5 '12 at 5:20
• I wish we had "No longer relevant" closing reason here... – Asaf Karagila May 5 '12 at 7:16
• @Jonas: questions with no answers can get bumped. But I think the bumping mechanism factors in also votes on the question and/or views or something like that (questions are not bumped entirely based on a uniform random distribution). So there may be some sort of bias on that. – Willie Wong May 7 '12 at 7:35
• @WillieWong: Do you have evidence or a reference? I've never seen it happen. – Jonas Meyer May 7 '12 at 20:26
• @Jonas: evidence are hard to come by, mostly because the community user bumps are not recorded in the history, so unless I take a screen shot as it happens (and as bumps happen hourly, it may take a while), it will be hard to give you evidence. But in so far as references go: meta.stackexchange.com/questions/19738/… states that the community user bumps unanswered questions, where "unanswered" is defined blog.stackoverflow.com/2008/09/ok-now-define-answered as questions with "no accepted answers and no answers with upvotes". – Willie Wong May 8 '12 at 8:53
• And from Jeff's answer on this question, meta.stackexchange.com/questions/31480/… zero answer questions are definitely not blocked from being bumped. But if you mean for evidence/reference for the second part of my previous comment, I plead "I think..." as in "My experience makes me want to conjecture that..." – Willie Wong May 8 '12 at 8:55
• @Willie: Thank you. I did mean for the first part. My experience has been that questions with very low (or high or medium) views/vote count, but with a single answer (or more) with $\leq 0$ vote count, can get bumped often, while questions with high views/vote count but with 0 answers exist, and I have never seen one bumped. I've never heard an official reason, but I'm not the only one to have noticed. (Although not very active lately, there were times when I spent a lot of time on MO & here & this pattern seemed to persist. Though I won't be too surprised if what I saw was a coincidence.) – Jonas Meyer May 8 '12 at 14:07
• @JonasMeyer you are right, at least now and since a very long time (quite sure also at the time of that discussion). This question with no answer can get bumped is a myth that's hard to eradicate. The cause is I think confusingly phrased documentation and that it seems plaisible it would happen. – quid Aug 21 '17 at 14:48
• @WillieWong I don't know what was current in '09 but you might overinterpret that answer. Anyway I am quite confident in '12 it was already as it is now, that is, question with no answer are not bumped. See meta.stackexchange.com/questions/217884/… and the answer linked there. It was also like that on MO 1.0 at least as of around '10 or '11. – quid Aug 21 '17 at 15:00
• @quid: you are probably right. The earliest unambiguous documentation I can find of the behavior you described however is Shog9 from '13 (which your link links to). (Not that I bothered trying too hard on this.) – Willie Wong Aug 23 '17 at 12:45