[jvan]

>For example, people spent hours exploring wikipedia, this could never be done with physical paper.

I must not understand what you're saying here. I'm envisioning someone reading an article, seeing a reference to something unfamiliar, then stopping to read another article in a nearby source about that thing or any other random topic, recursing for hours. This is easily done, and often was by children a few decades ago, with any encyclopedia set.

[est]

> This is easily done ... with any encyclopedia set

I get your point, the problem is that, a good set of encyclopedia is NOT available to every household everytime, it takes lots of space and storage. You can't go to a park with a set of encyclopedia, on the other hand, an iPad with offline wikipedia, navigating by clicking links is much, much easier than stacking many, many opened books on your fixed desk.