The article argues that the first social network dates to 1971. At Stanford's AI lab, engineers shared a machine running the WAITS time-sharing system, and the WHO command produced an unreadable list of logged-in users. Les Earnest wrote a program that showed real names, locations and idle times, named after people running their fingers down the WHO display to spot colleagues. It told him whether it was worth walking down the hall.

Ken Harrenstien formalized the protocol in RFC 742 in 1977, when only SAIL, SRI and MIT's ITS machines supported it. RFC 1288 followed in 1991 as the definitive specification. The protocol is trivial: the client opens a TCP connection to port 79, sends a username plus CRLF, and the server replies with plain text and closes the connection. It carries no encryption and no session state.

Content came from two files in the user's home directory, .plan and .project, meant to announce current work. Users turned them into diaries, jokes and ASCII art, readable by anyone via finger user@host. John Carmack's .plan, written from 1996 to 2010, became a development journal for id Software. On August 18, 1997 he used it to announce the Doom source code release. The files survive in a GitHub archive.

Around 1982, students at Carnegie Mellon wired microswitches into the department's Coke machine and exposed bottle counts and cooling times over Finger, making it a candidate for the first IoT device.

Finger fell over security. The Morris worm of November 2, 1988 exploited a buffer overflow in fingerd, likely the first malicious buffer overflow in history, infecting around 6,000 machines, roughly 10 percent of the internet at the time. Finger also leaks names, emails and login times, a risk RFC 1288 itself warns about. By the late 1990s most admins had disabled it. In 2020 researchers found attackers abusing the finger.exe that still ships with Windows 10 as a living-off-the-land downloader, used by the Astaroth malware.

The small-web movement has revived it. Happy Net Box by Ben Brown offers hosted .plan files, Finger.Farm is a Node implementation by Jon Roig, and plan.cat bridges to ActivityPub so a .plan can be read from Mastodon. Clients remain preinstalled on macOS and most Unix systems, installable on Debian via apt install finger, and Emacs ships M-x finger. The piece closes with setup guides: hosted accounts, running ffingerd under inetd on Debian, and a minimal Python asyncio server on port 79.