You're forcing me to make a request to the ad suppliers server. I understand this isn't unique to iframes but I'd much prefer that any ad content is proxied by the server I'm actually looking at. I go on a lot in comments about the invasion of privacy that ads represent and I think iframes go a long way to perpetuating that poor privacy 'deal' so reject them with aggression. I often find I'm forced to use the mouse to grant them any focus (which is frustrating for me because I don't like using mouse pointers but I imagine it causes all sorts of havoc with accessibility).