Here’s my Slate piece on the great Harry Potter Lexicon debate.
Slate is a great publication but there’s not always room for a full legal analysis in the relatively short format. So here are a few additions to my comments in that piece, mainly meant for lawyers.
First, in my writing I suggest that the right way to think about the Lexicon is not as fair use, but rather as not a derivative work of Potter at all.
I think that’s right for the text of the guide, particularly the description and comment sections. However, the fan-drawn pictures in the guide are a harder case.
As I say in my copyright class, character copyrights are powerful and are often what decide cases. The question is whether the fan-drawn pictures are copies or adaptations of the characters in the book. The copy question is debatable, but is probably the case that the fan-art is technically an 106(2) adaptation of the characters from text into art.
That being the case, the question is whether the fan-pictures are far use, which is a somewhat lengthy question. This is one area where there would be a difference between the book and the web-site, if we accept that the book has a more commercial purpose. On the other hand there does seem something dumb about allowing there to be a guide but then forcing the guide to consist of nothing but pictures of things like Hogwarts.
The second point I left out of the Slate piece is the relevance of the Seinfeld trivia case Castle Rock v. Carol.  This case found a Seinfeld trivia game to be an infringing derivative work of the show.  Its relevance is obvious, as it is an example of a court finding a product that is quite different from the original to nonetheless be a copy.
The simple answer is that Castle Rock is just wrongly decided. The case wierdly finds that a trivia game is “substantially similar” to the show and therefore a violation of the reproduction right (occasionally, to back itself up, the decision does refer to the derivative work doctrine).
The basic test of infringement of the reproduction right is, in part, whether you have misappropriated the market; whether the product you have produced would be a substitute for the original. Only in the most contrived way can a trivia game be a market substitute for a TV show - and the opinion, while it cites some of the right opinions (like Peter Pan) just goes on to ignore what they say.
The harder question is what happens if we ask if the trivia game was a derivative work of the TV show. My answer, as I said in the Lexicon piece, is that it doesn’t fit into the statutory definition of “adaptation”; either the examples or the space created by the words “adapted, recast, or transformed.” As I read the statute, to be under 106(2) a work must in some way share the purpose of the original work but in a different medium or form.
By this analysis the Seinfeld Trivia game is not an adaptation of the TV show, and therefore is not infringing to begin with; hence there’s no need to discuss fair use.
I accept that Seinfeld has not been overruled in the 2d circuit; though the 7th Circuit in Beanie Babies obviously views the case as erroneous without overruling it.