A lot of the ranking "criteria" is essentially something like "if Alice likes foo and bar and bob likes foo, then Bob will probably also like bar, so show him b

A lot of the ranking "criteria" is essentially something like "if Alice likes foo and bar and bob likes foo, then Bob will probably also like bar, so show him bar first". A lot of properties, like the emergence of conspiracy theories or social media fueling political polarization, are a direct consequence of such rules working as intended. One doesn't need an explicit is_flat_earth_related variable to still contribute to the spread of flat earth videos and show them to those who are the most vulnerable.