Many websites display copies of Gary Larson's famous "Far Side" cartoons. Here is an example. Some of these purport to encourage visitors to buy copies of Larson's books; others do not. Larson objects to this nopermissive use of his creations and has pleaded with his fans to cease and desist. One such fan -- Reto Portmann -- agreed to remove Larson's cartoons from his website; he then posted Larson's letter in its place. The reactions of subsequent visitors to Portmann's site vary substantially.
(adapted from a case study by Elizabeth Rosenblatt)