On Webmasterworld there are 2 threads on this one for the
advertisers and one for the publishers. Google Adwords has added a
feature so that advertisers have a blacklist of sites that they don’t want
their ad on.
There are many issues with this. Will advertisers throw away sales becasue
they are not smart enough to really check a site out before putting them in the
list. Publishers shoudl not be too concerned because most people that are
going to do this already have their ads banned on all content networks