i once worked on a project (about 15 years ago) where we had access to a reverse phone book listing that was generated in part by having a copy of every distinct paper phonebook in the US (also things like school directories) sent overseas to be hand entered (2-3 times for QC). A "nice" feature of it was that the address info was also geocoded so we could answer questions like "Who are my closest 100 neighbors and what are their home phone numbers?". Between that and Google buying the archives of usenet[1] in the same basic timeframe I realized that if it's written down its not likely to stay private for long.

Edit: add citation [1] https://en.wikipedia.org/wiki/Google_Groups#Deja_News