Taxation philosophy aside, I really like the idea of traceable ads in general. There are so many intentionally tangled and obscured intermediate steps between

Taxation philosophy aside, I really like the idea of traceable ads in general. There are so many intentionally tangled and obscured intermediate steps between the ad buyer and the ad viewer, a transparent record would benefit the honest parties and the consumer. Prosecuting, or at least deterring, malware served over sketchy ad networks comes immediately to mind. Is there ever a case where untraceability is a good thing?