I also wanted to share two follow up notes to the GRRM posts. First, check out this totally fascinating post from nihilistic_kid which basically demolishes GRRM's claim that H.P. Lovecraft died in poverty because he allowed unlicensed derivative fanworks of his books. I really recommend this post, not only for the information about Lovecraft, but especially for links and discussion in the comments that cast the infamous Marion Zimmer Bradley fanfic case in a somewhat different light.
The other is from GRRM himself. He's posted on this issue twice more since his original comment on the situation. The first was a standard attempt to simultaneously entrench and backpedal (he did acknowledge the copyright misconpetion, sorta), but the other is actually fairly thoughtful and interesting, and it's worth reading, if you can get past his annoying habit of referring to fan writers as "fan fictioneers". It's an emotional look at what his characters mean to him, and why reaction to fanworks can be just as much about love for the original creators as for the fan writers. Fan writers create out of love for the characters and the world; original creators feel protective of their creations for the same reason. While I still take issue with some of the particulars of his argument, I find it a lot more sympathetic than the usual "copyright/stealing/talentless hacks/write your own stuff/ZOMGporn!" tactics that pro authors often use against fic. Good debate in the comments, too. For starters, I recommend this comment, a semi-rebuttal from dagas_isa taking issue with the implication that pro authors who allow and/or encourage fic love their characters less than GRRM. And I agree: not more or less, although possibly different.