Mary Minow has written a very good blog post on this topic and includes pieces of U.S. copyright law that you will find interesting. In addition, there are well thought out comments on the post.
Many of use show off book covers on web sites and in blog posts. Having seen other people do it (and people who undoubtedly know more than I), I had assumed that it was legal. It good to see Minow bring up this topic and get us thinking about it. My personal feeling is that publishers and authors would want people see book covers, since that would draw more attention to the book. Of course, "wanting" and "being legal" are two different things!
Technorati tag: Copyright