Hybrids that include detachable keyboards have been sold since the 1990s. Convertible touchscreen notebook computers have an integrated keyboard that can be hidden by a swivel or slide joint. Booklet tablets have dual-touchscreens and can be used as a notebook by displaying a virtual keyboard on one of the displays.
Conceptualized in the mid-20th century and prototyped and developed in the last two decades of that century, the devices became popular in 2010.
As of March 2012, 31% of U.S. Internet users were reported to have a tablet, which was used mainly for viewing published content such as video and news.[5] Among tablets available in 2012, the top-selling line of devices was Apple's iPad with 100 million sold by mid-October 2012 since its release in April 2010,[6] followed by Amazon's Kindle Fire with 7 million, and Barnes & Noble's Nook with 5 million.[7][8][9] As of May 2013, over 70% of mobile developers were targeting tablets[10] (vs. 93% for smartphones and 18% for feature phones).[update]