I've recently setup simple forum, very painless.  However, when I try to post as a guest, the post itself does not show up until I leave the page and come back.  I do not have moderation turned on, and no errors are reported… thoughts?

you nailed it, great catch… simply adding sf-forum as a string not to be cached solved the problem.

can I sneak an offtopic question in here?

Did you ever manage to mark a php function as dynamic for wp-cache? I have a site where I want to activate wp-cache but every page contains 2 random images (so I can't just add a page to wp-cache and tell it not to cache it, I have to use this strange mfunc syntax he gives in his readme) so I have to make the function calling these ramdom images dynamic and I did never succeed :-(