One of the biggest changes in technical publishing in the last few years has been the "book of the blog". Joel on Software was the first to make it big, but there have been many more since. For example, I've just finished The Open Laboratory: The Best Writing on Science Blogs 2006, which was put together in just a few weeks for the 2007 North Carolina Science Blogging Conference. The quality is sometimes uneven, but it's as topical and entertaining as its more traditional counterparts.
I've wondered several times about blogging chapters or lectures as I write them; I even tried it out with the Software Carpentry lectures (though what I actually blogged was announcements about the chapters, rather than their contents). I'm not worried about it leading to "bitty" writing: lots of great literature started off in newspaper columns. What I do worry about is versioning: I have to revise material several times in order to find out what I'm thinking, but most people only ever read the first, or are upset or angered by contradictions between preliminary and final copies. On the other hand, as John Scalzi said in his announcement that he's running for SFWA president, "...the biggest problem facing creators is not piracy but obscurity."