You/I wish; no, it's just some posts that win the front-page lottery and the rest get flagged, and if flagged enough times (or by enough karma?) they get marked [dupe] by (presumably) dang
In the case of split lottery, someone emails hn@ycombinator.com and one setq [or update statement] later the threads get merged
[1] https://hn.algolia.com/?query=Windows%20NT%20for%20GameCube%...