In the iOS Appstore you can see which data they want to obtain.

World of Warcraft Classic. You start as a no one. Everybody around you seems to know what to do. Your items are shit. You look like a peasant. The silliest enemies force you to rest and are able to kill you.

It‘s challenging but so rewarding. It makes you feel grateful for every single lvlup, item and skill you can get.

Even after spending literal days of your life, there always will be people who are better than you. Everything is said and done. Still this game manages to pull me back in from time to time. It’s so much fun.

Startpage.com

The more there is known about you, the easier you are to be manipulated.

If you read George Orwell‘s 1984 or watch the Cambridge Analytica documentary on Netflix you get an idea.