It’s called microtargeting, all big tech companys are sorting people in groups, just by their use of the service. It starts with simple things, for example: cats or dogs? And this goes deeper to your religion or sexuality, politics etc. Created mostly for advertising it got used by political parties. Check the Cambridge analytical scandal. If you easily able to sort the people for your target you are able to manipulate your targeted people.
Newest scandal for microtargeting came from the EU-Commission with the chatcontrol.