bytex64.net/blog

Finger itself dates back to 1977, and is described in RFC 742. The idea is simple and familiar: "What's John doing right now?" Let's find out.

$ finger john
Login: john                             Name: John Warden
Directory: /home/john                   Shell: /bin/sh
Last login Sat May  8 15:19 (CDT) on tty34
No mail.
Plan:
I'm off kayaking in Colorado. Be back Tuesday!

The "plan" was a message that the user could post to give other people more information about what they're doing. This is probably sounding eerily familiar. Finger was pretty much Twitter and Facebook of the late 70's (except that it was only used by CS nerds on UNIX machines). Users' plans were one of the first instances of personal publishing on the Internet, an idea that would later evolve into blogging. Notably, John Carmack used finger to publish a journal of his work progress (archived here).

Finger died out largely because it was an information disclosure problem. As Wikipedia puts it, "Supplying such detailed information as e-mail addresses and full names was considered acceptable and convenient in the early days of Internetworking, but later was considered questionable for privacy and security reasons." That statement is absolutely true, which is why it gave me a chuckle — in our post-finger world, people apparently have no problem with putting their real name and email address online.

But finger isn't really dead... it's just extremely disused. You will still find finger and fingerd in the repository for most Linux distributions, and you'll even find the client program on Macs and Windows!

One amusing section in later revised versions of the RFC are provisions for finger use with vending machines:

Vending machines SHOULD respond to a {C} request with a list of all items currently available for purchase and possible consumption. Vending machines SHOULD respond to a {U}{C} request with a detailed count or list of the particular product or product slot. Vending machines should NEVER NEVER EVER eat money.

I'll bet Facebook can't do that. :-P