But they are also designed to promote information. In September 2020, Facebook tried to reduce the amount of misinformation on the platform by reducing the weight of the "angry" emoji in its recommendation algorithm. The result? Anti-vaccine posts stopped using it.

Pages can also be administrators of groups. Groups are designed to build communities around topics of mutual interest. Groups can coordinate with one another to blast out information, so removing groups is not likely to be effective.

Facebook has a "flexible layered hierarchy". That means that some people have a lot more influence than others. At the top of the hierarchy are page administrators that produce content, and are supposed to represent brands and celebrities. These pages form tight clusters.

Discussions about vaccines in anti-vaccine pages and groups also included more links to known sources of "iffy" misinformation and to sources that were widely considered to be politically biased

Maybe the content that was removed was less misinformative? Unfortunately, not. We saw that the content that remained was more likely to discuss sensationalized accounts of hospitalization and death, and serious adverse reactions falsely attributed to COVID vaccines.

But wait! Wasn't engagement already going down, and didn't it continue to go down after the policy? Apparently not -- people appear to have just engaged more in other anti-vaccine pages (E) and groups (F). Engagement in groups seems to have stayed roughly constant.

Despite this content removal, engagement didn't change much from pre-policy trends, and it actually increased above these trends in anti-vaccine groups.

Facebook removed a lot of anti-vaccine content roughly contemporaneously with the rollout of new vaccines. The amount of content remaining dropped well below pre-policy trends.

Pro-vaccine content also appears to have decreased (especially in Facebook pages).

Hello world!