> How does the HN system work when I submitted the exact same URL

This is a frequently asked question. The answer can be found in HN's FAQ: https://news.ycombinator.com/newsfaq.html. Reposts are allowed if a story hasn't had significant attention yet, because we there's a lot of randomness in what gets noticed on the /newest page and we want to give good stories multiple rolls of the dice.

Lots more explanation over the years: https://hn.algolia.com/?sort=byDate&dateRange=all&type=comme...