Toby Russell, VP of Digital at Capital One, gave a great talk on what makes a platform truly disruptive. To illustrate the difference between an application and a platform, he gave the example of Taxi Magic, an application he founded a few years ago.
Taxi Magic worked as a taxi booking app. However, there was no management of the taxi drivers. The result was that drivers would occasionally not turn up to bookings, reflecting badly on the app.
Contrast this to Uber, which manages the whole experience of booking the car, managing the driver, offering directions for the drive, processing the payment and rating the experience afterward, and you can see the difference. By managing the end-end processes and systems using contemporary technology, Uber ends up disrupting the whole industry.
This is the point of Toby's talk: disruptive innovation involves addressing customers' or users' needs using contemporary technology in a novel manner.
Non-disruptive technologies typically attempt to digitise existing solutions, and these sorts of solutions tend to act as an intermediary stage before a truly disruptive player turns the market in its favour. (An example of this is online banking, which for the most part attempts to re-introduce typical bank teller activities in a digital format).