[ghaff]

>it can be solved with trust, contracts and auditing

I actually agree with you. And large businesses in particular are both audited and do internal audits all the time. It's not that they and their employees are all untrustworthy but audits can both catch mistakes and send a signal that people are watching.

There are probably other mechanisms to do fraud detection. But, as your comment suggests, they may be more heavyweight and therefore might exclude most smaller sites.

[jefftk]

I don't see how audits work well in this situation. I wrote more about what ad fraud can look like in this comment [1] and I don't see how an audit would catch "as a publisher, one of our traffic sources is sending us bots instead of real visitors".

[1] https://www.lesswrong.com/posts/dFgfQTo4DRZG5t8Ap/can-ads-be...