Andy Matuschak:

Books are static. Prose can frame or stimulate readers’ thoughts, but prose can’t behave or respond to those thoughts as they unfold in each reader’s head. […] How might we design mediums in which “readers” naturally form rich associations between the ideas being presented? How might we design mediums which “readers” naturally engage creatively with the material? How might we design mediums in which “readers” naturally contend with competing interpretations? If we pile together enough of these questions we’re left with: how might we design mediums in which “reading” is the same as “understanding”?

The state of ebooks is truly sad. Nothing has changed in a decade (to be optimistic) and the digital book is still just a scan of the paper book trapped in a screen.