Yesterday three threads on Sean Penn were posted, all citing the same article from the NY Post. I posted a fourth thread(if you can't beat em...) that was pulled after around 9 posts.
A duplicate article, if noticed, will be pulled if the latest copy of it was less than 3-4 hours previously. This applies to relatively recent stories, however. For older stories, if it has been posted within a few days, or for really old stories, within a few weeks, then it will be pulled.
Search for articles before posting. If there is a duplicate, consider how fresh a story it is. If it is not very fresh, don't post the duplicate. If it is, then see if the thread has been in the last few hours and if it is, don't post it.
Thanks, AM