I made a formal complaint to BT. The reply I got was they would pass concerns to teamthat deals with web advertising. It sounded as if the problem was caused by that space being sold to an advertier, then they use it for the dubious adverts we are all plauged with.
This sounds similar to the response I got when I first raised this issue with BT about a year ago - it is more like passing the buck, as you then never here from the other department. I had a similar issue with another company several years ago that appeared to have a 'policy' of acknowledge and then ignore - I did pursue this (and managed to get some compensation for several people) but it is a time consuming process and should not be necessary.
BT/Yahoo certainly should be taking more notice of the content that appears on their pages - with so many users, they are quite a broad platform (with, I am sure, some young users), I'm sure if there was any attempt to use these sort of images on a TV advert there would be a major media campaign against it.