Rogers introduced the concept of the Innovator in his book "Diffusion of Innovation" 
first published in 1962.
In his curve, he defined five types of customers, the Innovation, Early Adopter, Early Majority, Late Majority, and Laggard.
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While the number of Innovators is small, they play a critical role in influencing Early Adopters.
Geoffrey Moore then modified Rogers concept by introducing one more important element, The Chasm.