I'm surprised anyone is surprised! For years I've been doing that search on White Pages Phone Directory, and before the internet, at the library using the reverse look up books (I forget the proper name). You can do a reverse on a phone number or address.
I use it to get the proper spelling on a potential customer's name and correct address when they call and leave a call back number.
Nothing even remotely new, the books have been at the library for as long as I can remember, at least thirty years.