Hey /img/, I was just curious about this, and here seemed like a good place to ask. I was just earlier telling someone about how you can link to another board by quoting a post on it, instead of by using the URL, and then it came up again in a thread.

So, like you quote a post with >>postnumber, you can do it to one on a different board with >>>/board/postnumber.

The thing is it only works between certain boards. I was just wondering if anybody can explain this. I assumed it was because it only works between boards on the same server, but I've seen a link to /hr/ from /a/, which are on orz and zip, respectively.