Information density - yes. Character - maybe. Portability - not likely. Five hundred pages seems an absolute minimum these days to satisfy an author's machismo. On-line material is also a worthy opponent in this area.
Space is absolutely no problem.
And other media can be seamlessly linked in. This article looks at ways in which the World-Wide Web equivalents of textbooks are likely to evolve. Publishers are already moving some of their wares on-line. Even more radical efforts, such as students themselves writing Internet materials as part of their course, are underway. Wholesale transfer to the Web New media usually begin by copying forms from old.