Amazon’s revealed two new Kindle devices this week, for $139 and $189. The less expensive version is wi-fi only, but this third generation release of Kindle has brought some new features as well.

Storage capacity has been increased to 4GB, new custom options for readers have been added (such as line-spacing), and a WebKit-powered browser–the same rendering engine used for Safari and Google Chrome on many mobile devices.

Another important feature is excerpt-sharing, which lets you post interesting bits on Facebook and Twitter. Passages shared by your friends are aggregated in the Popular Highlights section, adding a distinctive social layer to your reading experience.

Given Amazon’s delve into the social networking world for recommendations and gifting, this is just another way in which digital media has been associated with and improved by online sharing tools.

The intersection of social media and consumerism has also enabled an expansion of the types of mobile apps and devices that can be successful. Contrary to early speculation, Apple’s iPhone and iPad did not destroy the Kindle, or any other major eReader devices.

The ability to tap into social networks and existing customer accounts has permitted third parties to build devices and services around this cloud data. As ComputerWorld quotes,

“The e-reader market is expanding, not contracting, despite the emergence of iPad and competitors,” said Jack Gold, and analyst at J. Gold Associates. “IPads and e-readers appeal to different market segments.”

Other factors have contributed to Amazon’s perseverance despite the rapid uptake of Apple devices–all the major eReaders dropped their pricing in order to compete with smart phone apps. Partnerships and distribution capabilities for published works have become the determining factors around who’s successful in this space. Right now, there’s a battle brewing amongst publishers, as they seek to align themselves with the best digital distributor possible, making the industry the latest to follow in the footsteps of record labels and film studios.