For the anonymous users, PeachyForum is "cached" - meaning, all forums/threads/posts are taken snapshots those are updated every 1 hour. Therefore, after logging out you might see your name on the "who is online" -list, the latest posts might have "disappeared" and even some edited posts in their old form. Try logging out... and you'll see what the forum looked like 1-60min ago.
Very unfortunate, but that all has been made for the performance gain... anonymous guest checking peachyforum few times per day don't even notice anything being wrong. Personalization takes lots of resources...
Again one more reason to register - you'll see everything in real time!
ps. all the above applies if you "logout" from the top right corner. It's another case if you only browse away, or close the window... you'll stay logged in for 10-15 minutes before the forum makes a guess you're no longer reading anything but gone.