IIRC* , posts get rejected if the same URL is in the part of the history in memory. HN loads its data off disk on-demand, and it gets restarted every once in a

IIRC* , posts get rejected if the same URL is in the part of the history in memory. HN loads its data off disk on-demand, and it gets restarted every once in a while. Dupes can get submitted more easily after a recent restart, if nobody else has caused that comment thread to load. This means there isn't an explicit time-out for reposts, just a non-deterministic cut-off. I'd guess it's roughly 6-9 months. * Please correct me if I'm wrong! Also, it's all too easy for a good post to get buried by a bunch of lame submissions, then fall off the new page before getting enough upvotes. It'd probably be worth making submissions cost a few points karma; the current system blindly rewards submitting anything others are likely to post.