Back in the old days, there was the Usenet Mapping Project, an attempt to link Usenet posters to something more permanent than a floating flamewar. So they would accept information such as name, age, and ICBM address from the participating posters. That last was for delivery of the newsletter: The USPS was banned from carrying email back then and the gas crisis was on, so they bought some surplus delivery vehicles (Honest Abe for inter-city routes, Trident III for longer distance work). Sadly, only a few issues were sent: The FCC claimed jurisdiction over anything sent via the ionosphere and the often risqué eunuchs mounting was Right Out.
Incidentally, this plan was dreamed up when The Sharper Image decided to market to the Soviet Union during the blockade; the biggest difference is that junk mail is MIRVed. (As in Griffin, who thought up the basic idea for a failed game show called JeoparJarts: Each team throws small darts to the opposing side that split into smaller darts in midair, each of which has a question a teammate must answer. This failed when Dodge sued for a trademark violation.)