Smackdown has outlined how Google is displaying your PPC ads on porn-related parked domains. How well do you think those clicks convert for you? And yet, you are paying for those clicks. Considering that Google does not allow Adsense publishers whose sites are porn-related to display Adsense ads, why is that a parked domain with an obvious porn-related domain name can? This is just another example of why so many Adwords advertisers opt out of the content network. Go read the Smackdown post, as it details the problem nicely. And then tell Google that you don't want them to waste your hard-earned PPC dollars this way.