Originally Posted by
Sunshine
If you click on a thread from the front page recent posts list and you're logged out, it will take you to the most recent post (last post of the thread). When you're logged in, it will take you to your personal most recently read post.
It considers your "most recently read" post to be the last post on the last page that you visited, so if you had even clicked another thread by mistake or through a link from another thread, it will still consider it read to that point.