Hacker News has its own algorithm to detect dupes, but it only does that for 1 or 2 days (Sorry I don't know the specifics). However it means that there is noth

Hacker News has its own algorithm to detect dupes, but it only does that for 1 or 2 days (Sorry I don't know the specifics). However it means that there is nothing to mark. Having said that, it is fine to repost a particular topic. What has been read by people in 2016, might still be interesting to read about in 2018 too, there might be people who didn't notice it in 2016 or people who didn't even visit the site in 2016. The time interval doesn't even have to be that long.