I’m going to quote this because O’Reilly deserves full credit for their consumer-friendly approach to electronic publishing. This is by Andrew Savikas, from the Tools of Change for Publishing blog. There’s more in the orginal post:
Earlier this year, one of our authors reported hitting some sort of undocumented limit when using the “Clipping” feature on Kindle. And then other readers discovered they were unable to load Kindle books onto either additional Kindles or their iPhone running the Kindle app because there’s a limit to the number of simultaneous devices a Kindle book can live on.
While I can’t speak about the terms other publishers have with Amazon (though it’s a safe bet at least some of those kind of restrictions weren’t Amazon’s idea), because we want O’Reilly Kindle books to be available without any DRM, we asked Amazon if those limits applied to our books, and if so whether they could be lifted.
Though it took some work on their end (and they deserve credit for being receptive to our request), I’m happy to say that there is now no simultaneous device limit or clipping limit for O’Reilly Kindle books, and those changes have been retroactively applied for anyone who’s already purchased one of our Kindle books.