Both programs also have restrictions, but have a straightforward pitch: If you buy something from one of their stores, you can download digital copies to multiple devices. So if your husband buys one of the "Game of Thrones" books for his Amazon Kindle, you could also read it on your Kindle Fire tablet, or read it on your Kindle app on your iPhone. Or your kids could download a "Guardians of the Galaxy" app to their iPad for free, if you've already bought one.
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About those restrictions: Amazon says its program will only apply to apps, books, audiobooks and movies and TV shows available via its Prime Instant Video program. So this won't work for music or any videos you've purchased or rented. Apple's fine print, meanwhile, notes that "not all content types are available in all countries," but reps wouldn't spell out what that means.
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Both companies also have systems designed to minimize sharing beyond your "family," so don't expect to hand out books you bought like they're an HBO Go account. Amazon, for instance, requires everyone sharing content to have Amazon accounts with same billing address.
But even with the asterisks and omissions, this is a good thing. Neither company is charging a premium for this, and both seem to be making a good faith effort to let you consume stuff you bought, when and where you like.
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*About those new Amazon devices and operating system updates — there are many of them, and they seem more evolutionary than revolutionary. But you can judge for yourself:
- A new version of Amazon's high-end Fire HDX tablet, which will start at $379.
- New versions of Amazon's low-end Fire HD tablets, starting at $99.
- A "kids edition" of the Fire HD tablet — the same tablet as the grown-up version, packaged with a kid-friendly case, a two-year "no questions asked" guarantee, and a year of "FreeTime Unlimited," Amazon's subscription service that features kids' movies, games and apps.
- New Kindle readers: A high-end Voyage version for $199 and a low-end version at $79.
- New Kindle software features and new Kindle Fire operating system built on Android's KitKat.
—By Peter Kafka, Re/code.net.
CNBC's parent NBC Universal is an investor in Re/code's parent Revere Digital, and the companies have a content-sharing arrangement.