That is a google ad address that is showing in your browser history. Those are/were never actually displayed as pages, the address is simply where the google ad comes from that is on the Board. For some reason (flaw, bug in IE9) that remnant of the google ad happens to show in the history IE9. Since those pages were never actually displayed in the first place, when you click "back" button, the IE history realizes you never really visited those pages and removes them from the history.
It is essentially a very minor flaw in IE9 and doesnt effect its use or functionality in any way.