I have a couple of users that can barely see anything on the forums. I told them they were full of it but I logged in as one of them and half the posts are gone. It looks like they have thread tags they can't even see.

Ok wierd. It looks like you might have a filtering bug Chops. I clicked simple filter and then hit the filter button and suddenly I can see everything on his account.

Again this looks like more than 1 person is affected by this.