The use varies widely. They are private companies making money; most of their revenue is driven by ads, clearly, and most of the data harvesting is happening for that purpose. How do they deliver eyeballs to companies and individuals who are willing to pay for those eyeballs?
A lot of this will be about collecting your interests—what you like and what you don't like—so that when the time comes, they will show you a particular ad that is attractive, and you will be a ready buyer for that. One of the concerns I have is that this type of data is being linked across platforms and through your browser history. The linkage of data is quite concerning.
You asked about artificial intelligence. Can you repeat that part?