I finally found out what I wanted : The way they talk about their "archive" : http://www.amazon.com/gp/help/customer/display.html/ref=hp_rel_topic?ie=UTF8&nodeId=200386160 The important quote is that "There are rare circumstances in which content may not remain available for re-download. For instance, if the publisher who originally made the content available to us for sale on the Kindle Store did not have the right to do so or is sued for defamation in connection with the content, we may be obligated to stop making it available for re-downloading from your library. Any copies you already have on your Kindle devices will not be affected." They are following THAT line here, except that the "rare circumstances" stated in the paragraph is about "lawyering" whereas here it is company policy" that is used. Last, their terms of use DON'T seem to mention the "Library", so may NOT be legally bound to offer that "service" or to have any constraints on such "service" ...

Guys, It seems top me the front is NOT accurate : the books weren't deleted from the Kindles, but from the Archive. So people who had it loaded on the Kindle still get access to them. For the ones who removed them from their Kindle though, too bad... It's NOT that much better though since Amazon, B&N, Google et all seem to want to be the ones to control your "Archive" forever by having you access your books only through their servers... I wonder if they propose a way to download the total archive at some point ...