This is a bug, a difficult to solve bug. The server don't canonize the url, so you have: "http" vs "https", "example.com" vs "www.example.com", "example.com/whatever" vs "example.com/whatever/", "blogspot.com" vs blogspot.co.uk" vs ... , ...
The problem is that canonization is very difficult, it's very easy to get false positives, and each site needs a slightly different canonization rules. So the current method is to use manual moderation.
And when the server restarts, it forgets the old url's for a while, so there are some possible repetitions.
And in a very few times, resubmissions are good.
Most of the resubmissions are accidental, good faith resubmissions. Someone just copy the url and the browser / link / site internationalization was different.
I think there are not official rules, but the unofficial algorithm is:
* When a submission was recently discussed, and it's resubmited the moderators may kill it.
* If the discussion was a long time ago, the resubmission may be left alive.
* If none of the previous submissions get many comments / points, the resubmission may be left alive.
* If there is an intentional systematic resubmission, the moderators may hellban the user and put the domain in the autokill list and other nasty things.
The problem is that canonization is very difficult, it's very easy to get false positives, and each site needs a slightly different canonization rules. So the current method is to use manual moderation.
And when the server restarts, it forgets the old url's for a while, so there are some possible repetitions.
And in a very few times, resubmissions are good.
Most of the resubmissions are accidental, good faith resubmissions. Someone just copy the url and the browser / link / site internationalization was different.
I think there are not official rules, but the unofficial algorithm is:
* When a submission was recently discussed, and it's resubmited the moderators may kill it.
* If the discussion was a long time ago, the resubmission may be left alive.
* If none of the previous submissions get many comments / points, the resubmission may be left alive.
* If there is an intentional systematic resubmission, the moderators may hellban the user and put the domain in the autokill list and other nasty things.