You looking at picture x for x amount of time times 100000 and someother data they can get from you, can give companies a pretty good picture about who you are. In “good” cases this is just about advertising some brand to you, in bad cases they figure out your religion, political views, sexuality, work place and a lot of more things. With this data you can for example influence voting (this has already happend with Cambridge Analytica). Or “harass” people based on their religion this happens in some countries like China with Uyghurs. Find people that are of a certain sexuality that you dislike. Or something that (probably) hasnt happen yet but could happen in the US is figuring out who is pregnant (that is already pretty easy to determine) and in states where abortions are illegal prosecute people based on this data. Those are the extreme examples. Something else that could happen is that insurance companies could buy your data and figure out how often you work out or if you have signs of depression and increase your premimums based on that data.
The thing is that you can find out all those things based on information that you wouldnt consider sensitive like your scolling habbits.
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