@javi@goblin.band they measure the click through rate of ads. They don't have many ads so they all just send them to all browsers with some if then rules for showing them. Like for example, show amazon ad on new tab if amazon is in browsers local search history, all of which would be done on the browser side. They only get a signal if you click on the amazon ad on the new tab page. At most if they don't anonymize it enough then them would keep your ip but they probably don't.