If I click on "View posts since last visit" I get always the message "No topics or posts met your search criteria".
But it is not true, there are new messages, but this function don't work!
I'm using firefox, always the newest version. But with Iexplorer I have same issue. On different PC's (home and at work)
Could you change this useless option to "View newest posts"?
These has an other big advantage:
Sometimes I don't read every post since last visit, so I would want to do it later. But with having only the possibility "View posts since last visit" I can't do it.