Well, Apple has teamed with the O'Reilly folks to offer a Safari-style subscription service for searching and reading 1000 Mac-related books online.
Brad Shuler told me about nine months ago he thought such 'online bookshelves' were the wave of the future. I mostly dismissed the idea at the time, probably because I like reading a physical book and find I absorb the material better that way. I think I was wrong. Given the high cost of printing and the speed at which the software market is changing, I think this is the wave of the future, even if I don't want it to be.