[downandout]

Does HomeDepot.com get to see where else you go on the Internet because they have tracking code on their site? No, they do not. They cannot obtain this data from the major tracking vendors (Facebook, Google etc.) either. Granted, the vendors themselves can often see cross-site behavior, but the individual sites using these trackers cannot and aren't given access to this information.

[JangoSteve]

I agree with the other comments that the analogies kind of hide the ball on the real issues here. But in this case, I think it's more like Home Depot putting up security cameras that send all the footage of you to the camera manufacturer. In turn, that camera manufacturer runs facial recognition to automatically combine your Home Depot activity with your activity from all other business that use their cameras (which is 1/2 to 3/4 of the business you visit [1]), including the pharmacy, gas station, grocery store, bank, etc. Oh, and the information at the registers integrates with the cameras as well. And then the camera manufacturer sells your aggregate, combined data to advertisers who then set up shop at kiosks in the stores (the kiosks are owned by the camera manufacturer by the way), so that they can sell you stuff while you're there. And if the kiosk in Home Depot can't get you to buy something, they'll just get the kiosk at the bank to continue where they left off.

[1] https://trends.builtwith.com/analytics/Google-Analytics