Via Washington Technology, Joab Jackson :

In 1894, when Italian Guglielmo Marconi invented a way to send messages through the air, the Italian government turned down his offer of first rights because it saw no use for the technology. (...) Marconi's wireless invention represents what some historians call "disruptive technologies." These are technologies -- the internal combustion engine, transistors and the Web browser, for example -- that not only create new industries, but eventually change the world.

A "technological disruption" is the arrival of a technology so radically superior that it has the potential to render entire industries obsolete. It is hence a new product or service that disrupts an industry and eventually wins most of the market share. Clayton M. Christensen coined the term in his best seller, The Innovator's Dilemma, published in 1997 Via accesstoenergy.com :

Christensen defines two types of technology - "sustaining technology'' and "disruptive technology.''

Sustaining technology is that with a developed market. In well-managed companies which supply this technology, the products advance as rapidly as improvements in science and engineering permit -along the lines desired by the customers of the company. Managers carefully determine the desires of their customers and plan engineering development projects to satisfy those customers as quickly and cost-effectively as possible. These companies develop and infuse their work force with ethics, procedures, and goals consistent with this process in their respective industries.

Disruptive technologies, on the other hand, are usually simpler and cheaper than the sustaining technology, but also offer less capability. They do not fit the sustaining market and, typically, provide lower profit margins. For this reason, they are usually shunned by well-managed companies - which are often later destroyed by them.