As is laid out in the book, there was a big push post-2016, and rightly or wrongly, I think that to some degree there probably there should have been a realization earlier, but for whatever reason, the election of Donald Trump was a thing that for people inside the company, it wasn't so much like we should have tilted the levers, we should have adjusted the platform in some way to screw the guy over. You have a thesis about how Facebook works and you're on Facebook's core data science team, great, run a little experiment, pull out a 10th of a percent of all users in one country and enjoy running an immediate social science experiment on 50,000 people.