The video adverts that have appeared recently are a bit off-putting. They open automatically if you hover your mouse over them, but the ad's triggered a few time when I've been scrolling down forum threads, greying out the screen and placing an ad video in the centre. Currently EDF Energy, Go Compare, Special K, Persil and HP are on rotation. I've got Bit whitelisted (naturally) but on other sites which use it the ads, the block points to core.videoegg.com although looking at Bit's pages, these ones could be from doubleclick.net.
The More Than ones are incredibly annoying, and if you don't notice where your mouse is (which I often don't) you get something covering the whole screen that you can't get rid of until it loads, which takes quite a long time. edit: in fact, that isn't the only one... edit2: they are seriously irritating, and don't seem to have anything to do with a mouse-over. Frequently popping up when I switch to a tab with one on.