[babygene]

"Well, when you buy the book and lend it or give it to a friend, you no longer have your copy. It is the same copy that was purchased, and to share it, you must give yours up."

Well, with the web library I suggested, the works would be checked out and checked in. What's the difference?

[HairOfTheDog]

There may be no difference... in this scenario, are you sending real paper copies like a library or electronic ones? If you send electronic copies, it would be very hard to prevent copying, and the e-copy would not need to be returned before another person could use it. It could be infinately re-created.