Junk mail is borrowing tracking techniques from targeted online advertising
"They’re using the same technology and data as online advertising companies to target who gets what flier, postcard or envelope — even tying people’s online browsing activity to their home address. It means after you research Parachute’s bedsheets online, its ad won’t just follow you around on the Internet. It may also end up as a paper ad in your hands, delivered to your front door."
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