This sounds like a problem that should be addressed with machine learning and AI rather than the wack-a-mole style of matching strings. Separate out and distin

This sounds like a problem that should be addressed with machine learning and AI rather than the wack-a-mole style of matching strings. Separate out and distinguish possible humans from possible bots using a set of known humans and known bots. Assign a human likelihood probability to each user and pay out the click based on the probability. for eg. this user is 90% likely human, therefor the cost of the 20 cent ad click is 18 cents. This doesn't have to wait on Facebook, somebody could build this as a third-party app and then send refund requests to Facebook on clicks that are likely bots.