To get a really good grasp of what Disruptive technology means, I used the link on Fryer's page and found the entry on Wikipedia.
From Wikipedia, the free encyclopedia
A disruptive technology or disruptive innovation is a technological innovation, product, or service that eventually overturns the existing dominant technology or product in the market. Disruptive innovations can be broadly classified into lower-end and new-market disruptive innovations. A new-market disruptive innovation is often aimed at non-consumption, whereas a lower-end disruptive innovation is aimed at mainstream customers who were ignored by established companies. Sometimes, a disruptive technology comes to dominate an existing market by either filling a role in a new market that the older technology could not fill (as more expensive, lower capacity but smaller-sized hard disks did for newly developed notebook computers in the 1980s) or by successively moving up-market through performance improvements until finally displacing the market incumbents (as digital photography has begun to replace film photography).
By contrast, "sustaining technology or innovation" improves product performance of established products. Sustaining technologies are often incremental however they can also be radical or discontinuous.