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Q: Why doesn’t Amazon support the popular "e-pub" standard used by your competitors and many libraries?
A: We are innovating so rapidly that having our own standard allows us to incorporate new things at a very rapid rate. For example: Whispersync (which uses wireless connections to sync your place in a book across devices) and changing font sizes.
Other standards over time may incorporate some of these things. But we’re moving very quickly to improve the state of the art. It’s very helpful not to have to wait for some third-party standard to catch up.