Although Amazon are being unashamedly secretive regarding sales figures, there can be little doubt that they are happy with the performance of their Kindle ebook reader series to date. The original Kindle went on sale in November 2007 and demand was so high that it sold out in under 6 hours. It remained out of stock right up to April 2008.

The Kindle 2, widely viewed as an improvement to an already successful product, was released in February 2009 and was another great success with the Amazon customer base. In May of 2009 Amazon announced that its new, bigger Kindle DX would be released and started taking pre-orders for shipping on June 10 2009.

All things considered, by June of 2009 the Kindle was the must have gadget and was frequently referred to as the “iPod of books”. Meanwhile, in parallel with the development and marketing of the device itself, Amazon continued to add to its collection of Kindle titles. By early June of 2009 there were in excess of 300,000 Kindle titles available and the collection was expanding at the rate of, on average, 500 titles per day.

Excellent business for Amazon and a huge encouragement for repeat sales. Sure, you can buy books for your kindle elsewhere – but these might require translation, and why bother when the Kindle store has so many titles that you can download using 3G wireless connectivity in under a minute?

It’s also good news for all those third party manufacturers of kindle accessories – a rapidly expanding market. Amazon originally shipped a cover with the first Kindle, but discontinued this practice when the Kindle 2 was unveiled (no huge loss maybe as many owners didn’t like the cover and bought alternatives anyway). Customers who have just forked out out $359 for their Kindle 2 or $489 for their DX quite likely don’t think twice about spending another $20 – $40 on a protective cover for their expensive new toy. Like any portable kit, it’s sure to come in for a few bumps and scrapes in use – it makes sense to protect it doesn’t it?

Apart from the practical aspects, it seems that some Kindle owners are quite ready to pay over $100 for a designer leather cover – which will not only provide some degree of protection but will also make their high tech Kindle look more like a “traditional” book. As the Kindle is a fairly high ticket item most owners, will have some disposable income so it probably isn’t a huge surprise that they’re ready to pay for a few optional items to customise it.

Kindle owners can also choose from a wide variety of other accessories – clip on lights, metal reading stands and additionalfurther new models are introduced, it seems likely that more and more independent vendors will benefit from Amazon’s success.