Can you elaborate on what the documented harms and abuses are, and what the further risks are? People prefer seeing ads that are relevant to them compared to r

Can you elaborate on what the documented harms and abuses are, and what the further risks are? People prefer seeing ads that are relevant to them compared to random ads. This is not controversial, it's very much established. Of course, the benefits to the businesses, especially those businesses without existing brand recognition, are quite obvious.