They're one of the factors finally pushing me towards just a default-block policy (the other factor is sites that pop something up when you mouseover a link). I've tried really hard to start with a blank adblock list and individually block sites that have particularly egregious stuff, but the whack-a-mole is getting ridiculous. Haven't quite given in yet, but if I don't reach a fixed point soon where I can stop adding 5 new things a day, I'm just going to subscribe to a blocklist.

I wonder how hard it'd be, alternately, to write a heuristic to block absolutely-positioned top/bottom bars. May play around with that a bit.