J.K. Rowling has won her lawsuit to prevent publication of Steven Jan Vander Ark's Harry Potter Lexicon.
In not unrelated news, the online Harry Potter Lexicon is gone. Even the domain name appears to be available. I think this is a sad outcome even if, by my understanding of current copyright law, it's the right one. Rowling owns her characters, and most (printed) reference works dealing with copyrighted fictional characters are undertaken with the permission of and payment to the copyright holder. There are a number of gray areas, such as collectible memorabilia, where fair use holds, but at least in my mind, there is a huge difference, for example, between a photo guide to Mickey Mouse toys, or even an examination of the character of Mickey Mouse through an historical evaluation of variations in specific cartoons over time, and a book that provides "biographies" of Disney cartoon characters. (This is a simplified analogy, but Vander Ark seems to have lost his case because he was unable to demonstrate sufficient original commentary in his Lexicon to merit fair use protection of its publication.)
It's a shame that Rowling's victory seems to mean the end of the online Lexicon and not just the printed book, but in terms of maintaining the copyright, it may have been necessary. Vander Ark is correct that it is difficult to draw a meaningful line between the online Lexicon, which existed with Rowling's at-least-tacit approval, and even took in some basic level of revenue through advertising, and a printed edition. As a wanna-be author, I can understand the difference between allowing a tribute site to exist, and even take in enough money to pay for its server space, and between letting someone print and sell their own book using your characters, but, legally, copyright only exists if it is asserted and protected by the author. (This is the same reason that Band-Aid always includes the word "bandages" in their advertising. If "Band-Aid" were to be legally established as a generic term for what the British call a plaster, then everyone can call their products band-aids.)
Most people who construct sites like the Lexicon, including Vander Ark, include some sort of acknowledgment of the copyright holder and a disclaimer to the effect that the site exists because the copyright holder hasn't asked that it be taken down (along with implicit gratitude for the copyright holder's indulgence or benign ignorance). I don't know that this is the best of all possible worlds. In particular, some artists, like Prince, hold a tight grip on their material, perhaps even in excess of his legal rights. But absent legislation or tort precedent clearly delineating online copyright and fair use boundaries, we may have to continue to behave as if it were a print world.