Originally Posted by HarryT
A library system has to have the capability of "checking out" books to a restricted number of users simultaneously. If they have only bought, say, 3 copies of the book, they need to be able to restrict it to 3 simultaneous lenders. Time-limiting DRM enables this; can you suggest a reasonable alternative?
Just count the number of times you lend a book and have a minimum time for the lending. In that way you get the same effect as for paper books.