Toronto-based Kobo, the e-reader and digital book company, is one of the first users of Rypple Flow.

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By contrast, Amazon's digital book business is largely focused on its Kindle e-reader and Kindle software that runs on some other hardware.

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As well as being used for in-store signage, E Ink's technology powers Sony's e-book reader, and in April, Seiko, a watchmaker, unveiled a digital watch built around an E Ink display.

ECONOMIST: REPORTS