I think one of the greatest enemies of this part is "Search". When you can jump right to the part you want, you often miss a lot of unrelated but interesting things that surround it. You don't get the opportunity to subconsciously remember stuff. I have a love-hate relationship with online dictionaries because I miss running my finger down a column of words and learning a word or definition I didn't intend to learn.

That reminds me of something somebody once said, that I've since been unable to find again. I think it was during the postmortem of one of the first golf tournaments on fwp. A golf master (who presumably did already know all this stuff) recommended working on a golf problem by reading through perlvar, perlfunc, and all the core module doc, examining each item for applicability to that one particular golf problem.