Originally posted by Hook
While I can understand where you're coming from with that, at the same time most users are already going to be used to automatically clicking the sidebar to get around the site. This includes the Forum Index, or hell—the actual main page.
Making the banner clickable wouldn't stop the people used to click the Main Page link in the sidebar from still doing so. Not to mention a clickable banner should be very convenient for mobile users.
(I don't actually stand for what I've said in that other thread anymore)