I’m wondering if it’s actually physical mail that’s at issue, or rather having your home address as say a billing address on a site you buy something from.
This one seemed fairly tough to avoid 100%, so I want to know more about the plausibility.
Some industries (utilities, banking) are prohibited from selling customer info. But most aren’t. If you ever subscribe to a magazine, donate to a charity, enter a sweepstakes, etc your info goes into commercial lists.