You are listed as a guest, which means the system is seeing you as an unpaid visitor, like me. I would assume this is the reason for the ads being displayed.
Perhaps your subscription ran out, and it’s time to re-up?
Me too, but I get them when I click from the main page to the forum page. I think that’s before the system knows who I am. What’s odd is that it only happens about half the time and when it does happen Firefox tells me it just blocked a popup.