This article identifies three uses of educational technology and evaluates their potential to change curricula and pedagogic strategies. The article is in four parts, with the first outlining a temporal model of change and discussing educators' expectations of continuities and discontinuities in practice. In order to distinguish minor modifications from culturally significant changes in practice, the second part recaps a variant of Merlin Donald's cognitive-cultural theory of human evolution. The third part adopts this theoretical perspective and classifies uses of multimedia-hypertext systems, generic software, and computer modelling software, as instances of functional substitution, delegation and innovation. The fourth and final part of the article evaluates the change potential of these types of use, with substitution sustaining existing teaching strategies and curricula, with delegation modifying practice, and with innovation prompting culturally significant change. The article concludes by suggesting that functional substitution and delegation dominate present-day uses of technology and that functional innovation will continue to present both challenges and opportunities to future generations of educators. (Contains 1 table and 1 figure.)