Electronic paper is an ultra-low-power display that requires electricity only to change. ePaper is useful for eBook readers, grocery store price tags, and other displays that need not rapidly change and cannot be plugged in.
Electronic paper is a lesser-known Xerox PARC invention. Helping cement their reputation as the Worst Managers of All Time, Xerox never realized any benefit.
ePaper does not require electricity to power the screen unless it is changing. Consequently, it is optimal for displaying information like written text or prices.
In 2002, aware of the other innovations they failed to commercialize, Xerox spun off ePaper to a wholly-owned subsidiary, Gyricon LLC. However, the business down in 2005 due to undercapitalization. Subsequently, Amazon launched the Kindle two years later, in 2007 with technology by Gyricon competitor E Ink. Xerox patents had presumably expired by then.