I think it's because one person might come up with a more convincing headline than another that causes the post to take off here. If that's the case, the first

I think it's because one person might come up with a more convincing headline than another that causes the post to take off here. If that's the case, the first one to submit shouldn't always win. Also, if multiple threads on the same topic take off at about the same time, mods sometimes merge the two.