Advertising and marketing companies aren't the only ones that do this. Any corporation which owns more than a couple websites collects bits of information about them from each site and then builds profiles of its users, often then selling the information.
Say you own a sports website, a fashion website, a political website, and a gaming website. The user only specifies a tiny bit of information on each website. Each bit is collected into a single user profile from which they can refer to do things like figure out what product advertisements to show them. They use the same techniques to identify users that don't have accounts, and still collect their viewing/interacting habits and add them to the profile.
Sometimes they'll send you an e-mail telling you to check out their gaming website if you're not signed up, because the comments you write in their other websites' forums have to do with gaming. Sometimes they just sell the information to a gaming company. In the case of Target, they might send your teenage daughter a list of baby products for the little one you didn't know she was expecting.
This is not some horrifying violation of privacy. There is a price for all the free shit you get from the internet. Usually it's paid for by all the personal information you leak onto the net. They're just mopping it up and selling it back to you.
Say you own a sports website, a fashion website, a political website, and a gaming website. The user only specifies a tiny bit of information on each website. Each bit is collected into a single user profile from which they can refer to do things like figure out what product advertisements to show them. They use the same techniques to identify users that don't have accounts, and still collect their viewing/interacting habits and add them to the profile.
Sometimes they'll send you an e-mail telling you to check out their gaming website if you're not signed up, because the comments you write in their other websites' forums have to do with gaming. Sometimes they just sell the information to a gaming company. In the case of Target, they might send your teenage daughter a list of baby products for the little one you didn't know she was expecting.
This is not some horrifying violation of privacy. There is a price for all the free shit you get from the internet. Usually it's paid for by all the personal information you leak onto the net. They're just mopping it up and selling it back to you.