Just my 2-pennorth – I only get the pop-up once when I log in (and promptly cancel it – keithmart is right about its impact). Depending on what I am doing, I use either the ‘back’ button on the browser, right-click and ‘back’, and sometimes the ‘home’ button to get back to the Home page, and I never get this pop-up. I can’t believe I am just lucky, so the only thing left is setup. I have XP on one machine, and use Firefox as the browser (no microsoft rubbish if I can help it), and Vista with Firefox on my laptop.
The best answer by far is for someone to have a quiet word with the marketing department and tell them to break with tradition, and stop wrecking a good site with unwanted, unread rubbish – please don’t go the way of other good sites, and alienate readers.