From Wikipedia http://en.wikipedia.org/wiki/Diffusion_of_innovations
Diffusion of Innovations is a theory that seeks to explain how, why, and at what rate new ideas and technology spread through cultures. Everett Rogers, a professor of rural sociology, popularized the theory in his 1962 book Diffusion of Innovations.
Diffusion of an innovation occurs through a five–step process:
1. Knowledge: In this stage the individual is first exposed to an innovation but lacks information about the innovation. During this stage of the process the individual has not been inspired to find more information about the innovation.
2. Persuasion: In this stage the individual is interested in the innovation and actively seeks information/detail about the innovation.
3. Decision: In this stage the individual takes the concept of the change and weighs the advantages/disadvantages of using the innovation and decides whether to adopt or reject the innovation. Due to the individualistic nature of this stage Rogers notes that it is the most difficult stage to acquire empirical evidence
4. Implementation: In this stage the individual employs the innovation to a varying degree depending on the situation. During this stage the individual determines the usefulness of the innovation and may search for further information about it.
5. Confirmation: Although the name of this stage may be misleading, in this stage the individual finalises his/her decision to continue using the innovation and may end up using it to its fullest potential.
The rate of adoption is defined as the relative speed with which members of a social system adopt an innovation.