Hmmmm. If you post a BS message, Mudcat assumes you want to go back to the BS section, so it sends you to this URL; http://www.mudcat.org/#BS. I'll betcha that's what you saved as a bookmark.
You can edit your bookmark and remove #BS, or you can delete the bookmark, go to www.mudcat.org by typing the URL into the address box, and then save THAT as your bookmark. If you're lazy and don't want to bother with all that, you can get back to the top easily by hitting [CTRL-Home] on your keyboard.

Good luck, Michael.

-Joe-