Even a somewhat frail Steve Jobs isn't beyond calling Amazon.com (NASDAQ:AMZN) out on its Kindle.

"I think the general-purpose devices will win the day, because I think people just probably aren't willing to pay for a dedicated device," he told New York Times columnist David Pogue yesterday, when asked about his opinion of e-book readers. "You notice Amazon never says how much they sell; usually if they sell a lot of something, you want to tell everybody."

Poor Amazon. It's typically quite the Chatty Kathy when it comes to dissecting holiday sales trends or healthy releases. It's been surprisingly tight-lipped when it comes to Kindle sales over the past two years -- and that's something I've been calling Amazon out on since last year.

Then again, I'm no Jobs. If anyone can get CEO Jeff Bezos to pay attention, it's his arch rival Apple (NASDAQ:AAPL).

Yes, Amazon and Apple are competitors these days. The leading online retailer sells a bunch of MacBooks and iPods, but it also competes with Apple in the digital delivery of music, movies, and games.

In other words, Jobs may have his motives in singling out Amazon when the harmless Sony (NYSE:SNE) is also a beefy player in e-readers. If the Sony Walkman's rebirth in Japan continues to nibble away at Apple's market share, you can bet that Jobs will have a zinger ready for Sony as well.

This doesn't mean Jobs is wrong. Convergence is everything these days. Apple's iPhone is so popular because it's a computer, Web browser, media player, gaming device, and -- oh, yeah -- a phone.

The Apple TV is a failure, because -- channeling Jobs again from his Kindle swipe -- "people just probably aren't willing to pay for a dedicated device."

The winners are the devices that do more. TiVo (NASDAQ:TIVO) isn't just a digital video recorder. It also streams Web videos and Internet radio, and it's a playback platform for digitally delivered flicks.

Who says the Kindle is just a book reader, though? It already offers rudimentary Web browsing, and you can play music on it. A few Kindle generations from now, why can't it be a gaming device and a high-end media player that just happens to serve up digital books?

Either way, it's time for Amazon to just spill the beans on Kindle sales. Amazon's rivals may relish what they'd hear, but publishers and consumers need to know whether they should prepare for a more thorough commitment to the platform.

C'mon, Bezos. You're not going to let Jobs laugh at you. Are you?

Other page-turners in the Kindle saga:

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Longtime Fool contributor Rick Munarriz has been shopping online for about as long as Amazon.com has been in business. He owns a Kindle and shares of TiVo. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.