A deeper point is that the only way to know a subject thoroughly is to teach it to others. Often.

If you look at the most respected people in the Perl community, people like Randal and Nat and Chip and mjd and The Damian, you'll find out that they are teachers. They write books, give presentations, write articles, and still find time to produce code.

If you aspire to similar things, take an article or module documentation from one of those fellows and rewrite it in your own words. Rephrase things. Call your mother and explain it to her. Mentor someone with less experience.

This will do three things for you. First, you will learn a tremendous amount just by studying high-quality material. Second, you will test your understanding of the material by having to discover internal connections and external metaphors necessary to explain a new concept to another. Finally, you will hone the ability to recall where you first came across something. (Knowing where to look to find something is more important than being able to memorize facts -- there are more facts than you can memorize.)

merlyn is a good teacher because he is very effective at communicating to groups of people. I'm trying to develop that ability. :)