One of the most interesting things to me about this story is how anti-Rowling all the coverage has been. "Look at the greedy author, protecting her copyrights!" She used to be a media darling, but now they are turning on her.
I do think this article has interesting and compelling things to say about fair use, even if I don't believe this is the best case to champion the cause. What gets me is this: had the Lexicon been complied and presented differently, I would argue that it would count as scholarly commentary -- if it quoted less extensively from the books, if it included the essays on the site (with the permission of the authors, of course), if it were clearly branded as "unauthorized". But none of these things are true. Still, I have more mixed feelings about this case than I used to. Lawrence Lessig is a name that will catch my attention. If his organization is defending the Lexicon, then there might be something to it. Then again, he may be just the sort of crusader who will jump on any "raurgh, copyright holder evil!" bandwagon. As always, more research may be the answer.