What is a tablet?

iPad mini
Ancient stone tablet
Apple Bashful 1983
GridPAD 1988
Apple Newton 1987-1998
HP tablet PC 2002
Apple iPad 2 2013
Microsoft Surface tablet 2013
e-books on ipad
Reading a book on iPad

A tablet computer or “tablet” is a mobile computer with a display, hardware and battery in a single unit. Tablets are equipped with sensors, including cameras, microphone, accelerometers and a touchscreen, with finger or stylus gestures replacing computer mouse and keyboard.

Here we will use the term tablet to refer to the most recent generation of tablet computers often exemplified by Apple's iPad or the Microsoft surface tablet.

History
In 1983 Apple dreamed up what could be considered the first tablet-like computer called the "Bashful" which never made it to market the photos of these prototypes were only revealed in 2011 after Apple's success with the iPad.

In 1988 the GRIDpad was released. The touchscreen worked on handwriting recognition systems that where later used in Palm devices. Palm computing was later founded by the GRIDpad's creator Jeff Hawkins, a GRIDpad cost $2300 and was mainly used by professionals in healthcare and law-enforcement.

The Apple Newton developed from 1987 to 1998. Although it looks like the predecessor to the iPad it was actually one of the first personal digital assistants (PDA) on the market.

The MS tablet PC was developed in 2002. Most people think of this tablet when they hear the word "tablet computer".  It was basically a PC laptop with a swivel touchscreen. This sort of tablet computer never gained much market share, and many thought that no similar tablet computer would gain market share because of the failure of this and previous tablets.

In 2010 Steve Jobs unveiled the new touchscreen tablet called the iPad that renewed the way consumers viewed and used tablet computers. While the first-generation iPad had a few issues it eventually led to a boom in touchscreen tablets that we currently see today including Android based tablets.

E-readers
Tablets and E-readers are often lumped into the same category, but both have specific uses and features. Tablets are used for multitasking and general computing uses and E-readers are generally only used for reading. The cost between the readers and tablets is quite different as well, an average tablet will cost $800 to $300 and an E-reader costs $70 to $300.

Tablet Adoption
More than one-third of American adults now own a tablet, the rate has almost doubled from 2012 to 2013, according to a report published by the Pew Internet Center. In May 2010, only 3 percent of adults age 18 and older owned a tablet that number as of May 2013 is now 34%.

"One of the things that is especially interesting about tablet adoption compared to some of the patterns of other devices we've studied is how these technologies’ growth has played out between different age groups," Research Analyst Kathryn Zickuhr said. "With smartphones, for instance, we’ve seen a very strong correlation with age where most younger adults own smartphones, regardless of income level. But when it comes to tablets, adults in their thirties and forties are now significantly more likely than any other age group to own this device."

Pew Research Center 2013 by Kathryn Zickuhr Jun 10, 2013

Tablet operating systems market share (2013)

List of popular tablet manufactures market share (2013)
Apple: 29.6%
Samsung: 9.7%
Asus: 3.5%
Lenovo: 2.3%
Acer: 1.2%
Other: 16.8%

List of popular tablets (2013)
Apple iPad
Samsung Galaxy Tab
Google Nexus
Lenovo
Microsoft