This turned out to be one of the more interesting IP decisions IMHO. The Supremes decided that a list cannot be copyrighted if it’s organized in a simple and obvious way, like a phone book.

Which means that if you went to a bunch of trouble to license a ton of local phone directories, as you’d have to do back then, in order to create a national listing, your achievement would be worth exactly nothing. While I’m grateful to the Supremes for the decision as a dev, I can certainly empathize with Rural (the losers) as a businessperson.