To expand on this, I think you can eliminate a significant amount of this fraud by properly configuring your ad campaigns (or whatever facebook calls them) and using "tricks of the trade". The companies that spend the most on facebook ads, will likely allocate a good amount of resources to hiring people who are experts in facebook marketing. So you have a lot of people not being experts in configuring their ads getting fraudulent clicks/likes/followers/stalkers/customers/etc and losing money on advertising when they go down this route, but the big companies spending more money on facebook as they get better at new_revenue/ad_costs.