All that data collection is a leaky abstraction. People share browsers, look up stuff they have no ongoing interest in out of one-time curiosity, buy something

All that data collection is a leaky abstraction. People share browsers, look up stuff they have no ongoing interest in out of one-time curiosity, buy something as a gift, search for something they actually hate to find something about it to say in a debate about it, buy tickets for a movie they don't want to see because their friends want to, click on something outside of their interests just because it went viral, etc. And all that real world demographic data that gets bought and sold and tied to these online identities, it's not very accurate.