I worked on a project in 1990/1991 (pre-WWW) that involved making the phone book electronically accessible. For development my client purchased CD-ROMs containing the White Pages from the entire NYC tri-state area (NY, NJ, and CT), making it trivial for me to search by name and/or number. Once the web had been around for a few years, reverse-lookup became commonplace.

And then it disappeared once "Find out who called you only $50 or subscribe for $35 or we'll add you to our bad public records site" became a business model.