Hardly. It doesnt seem the law will affect the business, it will just make the cost of data collection explicit: "Pay $40/month to use facebook or get a free rebate by enabling ads".
Of course, they’d hate the idea of having a fixed revenue per user. They want to keep sucking out more revenue per user until the well runs dry.
Ergo, Facebook will charge a different rate per nation; per state; ideally per user (they already have all the data they need to calculate exact revenue per user based on their data).