A part of me has this initial reaction as well: "Who has not heard of the Jargon File?!" But then I remember that there was a time once (long ago now) when I hadn't heard of it either -- and I remember my own delight in discovering and inhaling it. At the risk of sounding patronizing, discovering the Jargon File is practically a rite of passage for nerdy youth. So to anyone reading the Jargon File for the first time: enjoy it, and (as long as you're learning about our shared history and culture) take a moment to also read the Story of Mel, the Last Real Programmer.[1]
Same here - I discovered it in 1991 by buying the paperback edition from MIT Press. I still thumb through it from time to time (I'd say it's good bathroom reading but I don't want my wife to flag it).
It's a wonderful pre-Internet artifact that I love having. I really don't care about updates or active-vs-printed stuff.
[1] http://www.cs.utah.edu/~elb/folklore/mel.html