> Usually Hacker News doesn't let you post the same link more than once.
I believe that's wrong. From what I've seen, I think that that time is also a factor. After some amount of time, you can repost things with exactly the same link and title. And I believe that it's deliberate (the posts are likely to be new to many people since the population turns over to some degree after x amount of time).
And that time period might be at most a month, considering the last post with the exact same link (http://news.ycombinator.com/item?id=5186774 ) predates the current post by 31 days.
I believe that's wrong. From what I've seen, I think that that time is also a factor. After some amount of time, you can repost things with exactly the same link and title. And I believe that it's deliberate (the posts are likely to be new to many people since the population turns over to some degree after x amount of time).