Different types of technological innovations affect performance trajectories in different ways. On the one hand, sustaining technologies tend to maintain a rate of improvement; that is, they give customers something more or better in the attributes they already value... On the other hand, disruptive technologies introduce a very different package of attributes from the one mainstream customers historically value, and they often perform far worse along one or two dimensions that are particularly important to those customers.

p. 44 - "Disruptive technologies: catching the wave," 1995