Yes, but a fad involves a rapidly growing market, whereas a rapidly growing market does not necessarily have to be a fad.

I don't think netbooks are a fad, but I also don't think they will last in the long term. Netbook manufacturers have been cannibalizing their higher-margin products with razor thin margins on their netbooks. This cannot continue if these companies expect to survive.

Not to mention netbooks have been absolutely destroying user experiences all around.