I discovered that the sites that have been blowing out my budget are those mass produced templated pages with nothing but ads on them. The problem is this: Yahoo calls these "sponsored search" ads NOT content ads. Traffic to them is included in the Sponsored Search summary. I can turn off Content Ads but I cannot turn off distribution to these garbage sites without turning off all Sponsored Search. This is what I was told by 2 customer service reps.
When I first saw a huge spike in clicks in late May, I called and asked them to check into it. Even though they gave me a credit for that spike in clicks, when the ads were turned back on, the clicks came, again, from the very same sites they gave us click credits for.
Yahoo, in their business policy, have defined these link-only templated sites as "partners" and reclassified ads distributed to them as "sponsored search" when they patently are not. This is a desperation move, in my opinion. We all know the pressure Yahoo is under to make money. This is a very bad move on their part.