All of the “social” media do it. So do the ISPs.
It is how they make money — lots of it.
Breaking the law is in vogue. Just ask Obama.
do a web search for something like a winter jacket
within a few days you will start to see ads for jackets on your web pages
LOL
I routinely go to my Amazon page, where I sell my fiction, to check for any new reviews and other postings.
I usually get ads sent to my email within 3 days - to buy my own books. It would seem the Amazon computer has yet to recognize my email addr is the same as the ‘author’s”.
Gotta love silicon....