On slashdot.org there was a talk about flash bassed adds and how popular they are becomming. It is harder to block them. Some simple solutions were talked about, but I see the advertisers have some simpler solutions. They havent been challenged yet.
My favorite trick is the F5 key. When an add is displayed, a cookie is usualy saved that says you have seen the add (or they track it another way). What F5 does is reload the page. Now you are viewing the page a second time and they think you saw the add so they will not show it again. Either that or they show the add every time and that would get annoying. Remember F5
Now that advertisers are switching, I thing spyware and adware will also make the switch. Imagin browsing windows updates and a free download add appears for you to click on. You click yes because it is microsofts site. you system is toast.