I'm not so sure. I always figured the cost per click would drop accordingly. If fraud is 50%, advertisers would only bid 50% for a click/impression, and it would be a wash in the end for the advertiser and Google.
I think the real hit is against content creators who aren't able to extract the full value of their work, instead they split the revenue pool with a bunch of adspam sites.
I think the real hit is against content creators who aren't able to extract the full value of their work, instead they split the revenue pool with a bunch of adspam sites.