I generally have four or five books open around the house--I live alone; I can do this--and they are not books on the same subject. They don't relate to each other in any particular way, and the ideas they present bounce off one another. And I like this effect. I also listen to audio-books, and I'll go out for my morning walk with tapes from two very different audio-books, and let those ideas bounce off each other, simmer, reproduce in some odd way, so that I come up with ideas that I might not have come up with if I had simply stuck to one book until I was done with it and then gone and picked up another.
So, I guess, in that way, I'm using a kind of primitive hypertext.
Learning and memory are by default automatic processes; their efficacy is proportional to the relevance that the thing to be learned has to your life (frequency, neurons firing together, synaptic pruning, interconnections, etc.). You could say that this relevance acts as filter for incoming information.
There are reasons why you might want to sneak information past this filter ("artificial learning"):
To learn abstract knowledge that is far removed from daily life (e.g. math). This is done using analogies, mnemonics, examples, anthropomorphism, etc.
To interfere with the process of "natural learning" with the goal of improving learning mechanisms, for example when learning a skill like playing the piano. This is done using deliberate practice, analysis, etc.
See these methods as gardening techniques. We either let the garden of the mind grow naturally or we sculpt it deliberately.