Slate has an interesting article on the Amazon and Apple patent applications for technology/processes that will allow for the resale of e-books via their respective marketplace ecosystems. This is something that has been discussed by a couple of authors on my Facebook newsfeed and the consensus seems to be "if it happens, I will no longer publish or sell my books on Amazon". It seems to me that this attitude actually misses the larger picture of what is (or at least might) happen in the e-book marketplace.
Amazon's patent (and now Apple's) is in response to a larger ecosystem of court cases on the "first sale doctrine" - a legal precedent set well over a hundred years ago and enshrined in the United States' copyright law ever since. For those who do not know, first sale doctrine at its most basic states that once a consumer purchases a good, that good belongs to them and they may resell or give it away without paying the original producer a second time. Now, of course it's far more complicated than that - there are other intellectual property/copyright/patent issues as well as international and export issues - but in its original form, that's what it was and - wait for it - it was originally about books! The original case was Bobbs-Merrill Co. v. Straus for those interested enough to look it up. As with all court decisions and laws, this has been changed, adapted, extended, and clarified numerous times since the original.*
The basic premise - that the first sale is the one that compensates the copyright creator/holder and exhausts that persons right to distribution for that copy - applies to physical goods like paper books, music cds, DVDs, etc. Amazon and Apple (along with other technology companies in music and movies) are creating processes that would allow for the application of first sale doctrine to digital works as well.
Why would they do this? Despite the "Buy" button on Amazon, consumers don't really purchase e-books - we license them. However, there are a couple of court cases currently being heard (or about to be heard) that are contending that the rights of consumers who purchase digital content should be no different than those of consumers purchasing physical content and therefore are arguing that first sale doctrine applies to digital content. The Slate article mentions one of these cases that focuses on digital music files - Capitol Records LLC v. ReDigi Inc. - and you can bet that any case that applies first sale doctrine to digital music files will be swiftly followed by applying it to e-books as well.
The point of this rather long-winded post is to say that Amazon and Apple are likely gearing up for the possibility that the courts will decided that digital content is covered by the first sale doctrine and they want to be ready to get a piece of the secondary market pie should that happen. Authors and publishers may not like the idea of "used" e-books but the courts may well decide that first sale doctrine applies to e-books in the same way it applies to paper books, in which case authors and publishers will have to decide whether to work with Amazon, Apple, and other vendors or not. Regardless of the decision of individual authors or publishers on whether to engage with specific vendors in a secondary marketplace, their e-books will still be part of the ecosystem and consumers will have the right to sell or buy them "used".
*I am NOT a lawyer but the basic legal information behind this post is readily available online.