I have a more benign theory than Michelle's (although she makes a good point).
It could simply be that people looking for bonsai information were "forced" to the web sooner than later, since it's easier to find bonsai info online than at the bookstore. In other words, the possible audience has by and larger already been reached.
People looking for music, news, and entertainment have augmented their access through the web, whereas bonsaisits had fewer outlets.
or something totally unrelated
pootsie