Technologies are developed based on old technologies. This is true because the capabilities of new technologies are limited by the existence of previous technologies. Also, adoption of new technologies is based on what makes sense to us, which is moderated by our past use of technologies. This logic has much in common with learning, but that is for another time.
We must be aware of this logic as it is destined to prevent fundamental change in education. Some people are excited about the ipad or the kindle fire because of the way it will allow development of digital textbooks. This misses the deeper issue of why we need textbooks at all? The smart board makes a lot of sense in light of the chalkboard, overhead, & LCD projector, but makes little sense in light of social learning theory. Perhaps we ought to be asking why we continually adopt technologies that reinforce the teaching wall & teacher centric classrooms?