I really like the term "spelunking" for this.

Pick unexplored corners of toolkit you use, unfamiliar commands, try to learn a new language out in left field from what you already know, etc. Even if you don't use them directly, it's good exercise for your mind, and new ideas you encounter along the way will likely come in handy some day. You never know when a connection to something seemingly unrelated will click and lead to a breakthrough. (http://achewood.com/index.php?date=06132002)

A former coworker would go into the bin directory and read through every command at least once a year, if I remember the exacts correctly. He was also the best system admin I remember ever seeing.

I believe I have 80% of the java spec read by the same strategy from when I was a full time java programmer.

I agree with the author of this article, but I have to wonder if there are very many programmers who don't do this?

There most definitely are, but the lack of interest in exploration is not necessarily permanent -- it probably only takes stumbling across one or two cool things to reward and reinforce curiosity.

Some people in every field lack the skills or motivation to teach themselves, though programming probably amplifies this difference because there are so many new things emerging and so many niches, and because with enough motivation you can often just download an interpreter, toolkit, or live boot cd and start experimenting with it.

I suppose that it's probably a lot different for programmers who didn't start programming on their own - those whose first exposure to coding some software was through classes in college or whatnot.

I know that for me, almost all of my knowledge of software development and knowledge about what tools are available on a linux system, and how they work (as well as about how the kernel works) came from this process of poking around, reading what was available to me, and then trying things out.

Same here. And MS-DOS before that, and a Commodore 64 before that. :)

The process never ends.