Good point Jojo,

There is however a big difference between the two ways of distributing the books. In mr. Williams case he distributes a single already paid-for item. In case of e-books there will always be distributed a copy of the text.

I don't think that anyone who bought an e-book and sold it second hands will delete the original electronic text.

I think that in the near future we have to re-evaluate the way data (books, music, video's) will be sold and the old system clearly fails therein. But for now we are stuck with the old system.