Kindle for Mac released: Is Amazon's e-reader moving away from hardware?

When Amazon debuted its first Kindle e-reader just over two years ago, we asked "...but will anyone buy it?"

We still can't say for certain.

Amazon CEO Jeff Bezos has made it very clear that Kindle users consume a lot of Amazon's e-books. But to date, Bezos has never gone public with hardware sales figures. So we can't be sure if it's Kindle hardware that's driving content sales, or perhaps the software Kindle for Windows 7, iPhone, iPod Touch, and BlackBerry.

A report from Credit Suisse Group AG in February determined that Amazon.com had a 90% share of the e-book sales market last year. So the question looms large: What is everyone reading these books on?

Today, Amazon announced Kindle for Mac, the latest addition to the family of free Kindle software. It's essentially the same software that was released for Windows back in November, which lets users synchronize content and bookmarks between their mobile Kindle device and their desktop. If a user is reading an e-book on his Kindle 2 or iPhone, he can pick up on his PC where he left off on his mobile.

The software gives users the ability to shop in the Kindle Store, access their library of previously purchased content, view notes and highlights, adjust font size and spacing, and unlike the Kindle device, read books in full color. Amazon says the software will eventually come to include full-text search and the ability to make new annotations.

Kindle continues its strong push in the software direction this year. Microsoft CEO Steve Ballmer showed off a mystery HP slate running Kindle Software at CES this year, and Amazon promises a version will grace Apple's hotly anticipated iPad. So Amazon looks ready for the tablet trend.

The Kindle hardware, however, doesn't appear to be blazing as many new trails right now. The educational pilot programs with the Kindle DX were largely unsuccessful, and Amazon job listings earlier this month showed the company was considering improvement of the Kindle's rudimentary Web browser "on a tight schedule."

It's obvious that Kindle is a vehicle for selling Amazon's proprietary e-books. But with no sales figures to illustrate consumer adoption of Kindle hardware, a saturated market of competing e-reader hardware of equally negligible relevance, and continuing growth of the free Kindle software, we may have to rephrase and restate Ed Oswald's question from two years ago...

People are buying Kindle books, but are they buying Kindle?