I don't remember everything I've done or why. There is very little training data to be found for us as persons. IF they hack your phone or computer they might be able to store how you interact with the internet. Which things you browse and read, what you buy, how you write on social media. They could possible then create a digital twin (a clone) of your online presence but it would be a lot of work for very unclear gains. If they hack enough people they could learn some connections like that people interested in electric cars might also be interested in battery technology and solar panels, people who are interested in vegetarian food might also like to read/write about vegan food or the environment and so on. But I still think it would be a LOT of work just to end up creating a fake website selling fake batteries or vegetarian food that you either never deliver or that ends up being a poor replica of the good stuff.