The author of the post http://mathoverflow.net/questions/108348/submission-to-arxiv-requires-endorsement-closed (who claims to have a super-short elementary proof of the Collatz conjecture) is starting to get angry in the comments.

Something should be done to keep this from going out of hand. As I said in my comment, I flagged it as spam, which I think fits the situation given that the author has a previous (now deleted) post on the same topic. If other people flag it as well, then the system will delete it and we can put this unpleasantness behind us.