The finger protocol, dating from 1971, allowed anyone on the internet to query a server for information about its users — real name, last login, current location, even the contents of a .plan file the user could update at will. It was used by researchers to share project updates, by students to check if their professors were logged in, and by the Morris Worm in 1988 to propagate itself via a buffer overflow in the fingerd daemon. Security-conscious administrators disabled finger throughout the 1990s. Those who didn’t provided a reliable directory service for social engineering attacks until the protocol quietly fell off the internet in the early 2000s. The .plan file lived on briefly as a precursor to the blog, the status update, and eventually the entirety of social media — which is either a charming origin story or a warning.
