You know how when you post a comment in this forum, it takes you directly to that post when you are done? This is done with anchors. By putting a # in the URL with the anchorname, it takes you directly to that spot on the page.
Your URL:
http://www.someurl.com/mypage.php#post453
Inside mypage.php, there is this tag:
<a name="post453">
When the URL is loaded, not only will mypage.php appear in the browser, it will automatically scroll to the post453 anchor.
I believe that is what he is trying to get to work...
[edit]
Ok, I just tried it myself, and it seems to work properly the way you have it set up, Hotkey. In fact, after editing this document, the URL for my post is:
http://www.phpbuilder.com/board/showthread.php?s=&postid=10317155#post10317155
So, to answer your original questions, yes you can send both through the URL, and you have the correct syntax. Perhaps you have the page cached... try clearing out your history, and try again.
If it is still not working, I don't know what to tell you. What browser are you using? I got it to work correctly in IE 6.0