When I go to this site http://www.khq.com/ (the website for a local TV channel), a Flash ad walks on after a couple of seconds, usually from the left side of the screen. On my old computer (older version of Adblock Plus?), I was able to block this and it never happened again. Now when I right-click the ad while it's running, there is no "block with Adblock..." option.
Sorry I don't know the name for this type of ad or any of the technical details. I have never seen an ad like this on any other site.
Thanks if there's anything you can do about it.
Bruce
P.S. I use Firefox and subscribe to the EasyList filter.