Huh, I always assumed that HURD was just GNU politics, what with the all the GNU tools with linux, while the GNU's original goal was an OS complete with kernel. When I look at it in this light, HURD makes more sense. I do disagree with saying that every OS advances the state of the art though, a lot of them will probably end up as *nix clones. I have respect for anyone who builds a kernel from scratch, but I also think that most of them ad totally batshit insane (Linus included.). They do great work, but I didn't understand why.