Personally, I have nothing against the canonical Harry Potter empire, but I'm hardly a huge fan. I've seen most of the movies on video, and have looked at a few of the books. If Methods of Rationality were just Harry Potter fanfic -- even great fanfic -- then I probably would have no interest in it at all. I don't have time to read half of the published fiction I would like to, and even today, publication on dead trees still tends to screen out some of the worst writing; and published works tend to go through a more thorough reviewing process, allowing the reader to cherrypick the most rewarding reads. Also, I like paper as a medium.