But improved interactivity
Hyperlinking gives a lot more flexibility in how you navigate material than printed matter. Also with some of those resources (perlmonks in particular) there is an opportunity to interact either through chat or posting. The ability to put out your understanding and receive targetted corrections where needed does wonders for accuracy.
That said, I prefer to learn significant topics from a book, then refine through online interaction.
Cheers,
Ben
"... I couldn't see how anyone could be educated by this self-propagating system in which people pass exams, teach others to pass exams, but nobody knows anything."
--Richard Feynman
