Ahh so now I know what's happening
the ?p=7825 queries a post, loads the thread it's in and puts the viewport at the post in question.
But what I didn't understand is that it is basically a redirect, which changes the url from:
http://guidedhacking.com/showthread.php?p=33051
to:
http://guidedhacking.com/showthread....3051#post33051
I didn't realize that would change the URL as well. My impression was that ?p= woud show just the post but that was incorrect.
Case Closed!