Key difference: Both the Kindle and Nook started out as E-book readers. The Amazon Kindle is a series of e-book readers designed and marketed by Amazon.com. The Nook is another series of e-book readers, and a major competitor to Kindle. The Nook is designed and marketed by Barnes & Noble.

Both the Kindle and Nook started out as E-book readers. However, overtime both the Kindle and Nook have evolved into more than just e-readers. They can now stand their own ground against the market influx of tablets.

An e-book reader is essentially a mobile electronic device whose main use is for reading digital e-books and periodicals. The main selling point of an e-reader is that they use electronic paper technology for screens. This allows the e-reader to display content without glare, quite similar to a printed book and/or a newspaper. Also, the device usually tends to have very long battery life. However, a disadvantage of a traditional e-reader is that it is black and white.

Eventually with the onset of tablets, which have the capability to double as an e-reader, many manufactures upgraded their e-readers to incorporate media support, including color screen, Wi-Fi capabilities, availability of apps, movies, music, etc. Essentially, the traditional e-readers became tablets.

The Amazon Kindle is a series of e-book readers designed and marketed by Amazon.com. The first version of the Kindle was released in 2007. The term Kindle referred to kindling a fire. The Kindle first started out as an e-reader, and then eventually developed into a tablet.

The current range of  Amazon Kindles includes eight devices: Kindle, Kindle Paperwhite, Kindle Paperwhite 3G, Kindle Keyboard 3G, Kindle Fire Tablet, Kindle Fire HD Tablet, Kindle Fire HD 8.9" Tablet, and Kindle Fire HD 8.9" 4G Tablet. Four of these devices are tablets. Each device offers a range of services, ranging from the traditional e-reader to HD tablets with 3G and/or 4G compatibility.

The Nook is another series of e-book readers, and a major competitor to Kindle. The Nook is designed and marketed by Barnes & Noble. The Barnes & Noble Nook is based on the Android platform. The first Nook was released in November 2009.

Nook follows the same story as Kindle, in which it originally started out as a traditional e-reader. It then launched a color e-reader, which eventually developed into a tablet. As the tablets run on Android, they offer access to the Google Play store, as well as the content and apps available in Google Play.

Currently, the Nook series offers four devices: Nook Simple Touch, Nook Simple Touch with Glowlight, Nook HD and Nook HD+. The Nook HD and Nook HD+ are actually tablets, a 7” tablet and a 9” tablet, respectively. The Nook Simple Touch is a traditional e-reader, whereas Nook Simple Touch with Glowlight is a traditional e-reader with an in-build backlight.

Each version of Kindle differs from each other, as well as from each version of Nook. Similarly, each version of the Nook differs from each other, as well as from each version of Kindle. That is also true of the tablets available under each brand.

Image Courtesy: knowledgetoday.wharton.upenn.edu, barnesandnoble.com