YouTube’s algorithm, especially, has an outsize influence. The platform is estimated to be second only to Google in web traffic, and 70% of what users watch is fed to them through recommendations.

In recent years, this influence has come under heavy scrutiny. Because the algorithm is optimized for getting people to engage with videos, it tends to offer choices that reinforce what someone already likes or believes, which can create an addictive experience that shuts out other views. This also often rewards the most extreme and controversial videos, which studies have shown can quickly push people into deep rabbit holes of content and lead to political radicalization.