Few will argue that the Kindle isn't a potential juggernaut for Amazon.com (Nasdaq: AMZN). The $399 proprietary electronic reader is Amazon's meal ticket for delivering digital books, publications, and beyond.

Reviews have been mixed for the device, but Amazon sold out of its initial stock in less than six hours the day the Kindle made its debut last November. Kindles haven't been readily available since then. They keep shipping out as they come in on a first-come, first-Kindled basis.

All is quiet on the e-book front
However, we don't know how many of those Kindles have been sold. This week's conference call should have changed that. CEO Jeff Bezos has been singing Kindle's praises for months, and the item has been tacked on the Amazon landing page since November. The latest earnings report gave the company a chance to really wow Mr. Market with some impressive metrics. The same Amazon that loves to sing its holiday praises the day after Christmas is rarely reticent.

Analysts were certainly hungry for information. They asked twice about the Kindle. First, they lobbed a softball request for "a little color" on the device.

"Kindle, in terms of demand, is outpacing our expectations," Bezos responded, before conceding that supply has been a problem as the company ramps up production to meet orders:

Our goal is to get into a situation as quickly as we can where when you order a Kindle, we ship it immediately. That's the standard we want to hold ourselves to, and we are working very hard to get there. We are super-excited by the very strong demand.

The analyst asked for color, but Bezos simply described the outside of the crayon box. Of course there's a problem on the supply end, but give us some numbers! How many units have been sold? How many are on backorder? If the numbers are big enough, the first quarter will be huge.

Amazon doesn't book an order for a Kindle as a sale. Instead, it only tallies fulfilled and delivered devices. So the November and December orders that got bumped to January could be material contributors to the company's top line this quarter.

Questioners later enquired about the Kindle's internal components. "Are there capabilities that have yet to be turned on beyond just the e-book reader and browser functionality inside the Kindle at this point?" one asked Bezos.

"The Kindle has a few experimental features," Bezos explained, as he delved into functionality of the Web browser built into the device.

Instead of telling us how many units have been sold -- or at the very least, the amount of titles sold through the Kindle electronic store -- Amazon kept uncharacteristically mum.

Light a Kindle like a candle
The importance to Amazon of delivering books electronically became even more obvious with yesterday's announced purchase of Audible (Nasdaq: ADBL). If the Audible deal had been declared a day earlier, someone would have likely asked about the possibility of incorporating Audible's subscription service into the Kindle.

Amazon probably would have skated around that question, too. It just doesn't make sense for a company pitching an in-house product to be so quiet. Unless Kindle is about to introduce an upgraded version, with fears of alienating the early adopters, what's the harm in speaking in concrete terms?

Wouldn't it only help Kindle to go public with the percentage of book and magazine sales that came from Kindle products at Amazon? Amazon's megaphone is louder than Sony's (NYSE: SNE) will ever be, when it comes to the rival Sony Reader, so why isn't Amazon speaking up?

What's the worry? Does Amazon feel that if the number is huge, Apple (Nasdaq: AAPL) and Microsoft (Nasdaq: MSFT) will jump into the fray with their big-screen portable media players? Does it feel that if the number is too small, new orders will taper off? If we're waiting for a milestone, how large a milestone will we be talking about?

It's ironic. The Kindle is built to tell stories, yet when it comes to actual figures, Amazon's staying silent.

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