[Air-l] blogs text?

I'm revamping my class in New Media and was wondering if anyone knew of any new books out there on blogs that one could recommend be set as a course text (i.e., a shorter book aimed at undergrads or a general public). I'm not looking for "How To" books, but perhaps a more critical approach to the phenomena. I've noted a number of books on blogs listed on Amazon. Also, or instead, if anyone knows of any decent articles on blogs that might work as a critical overview to set instead of a whole book, I'd appreciate it. Offlist replies are fine. Thanks, in advance, Greg Wise