Filter bubbles existed before, but they were nowhere near as narrow as they are today. Only fifteen years ago it was normal for most people to either watch or at least be aware of the same shows (including nightly news) as their neighbours, work colleagues, and school friends. That is no longer the case at all.

I think a lot more attention needs to be paid to the ML recommenders that companies like Facebook are deploying, and the assumptions going into these algorithms, and the externalities they are creating. In my opinion they are playing a similar role in our social crises as the Gaussian copula played in the financial crisis.