Like it or not, Blogs are now part of academia. The benefits of blogs are obvious: fast dissemination of information, the opportunity for informal public debate without the delay or constraints of journal publication or professional conferences, and the possibility of reaching a wide audience including the lay public. A major drawback, however, is quality control. Anyone can post anything they like without peer review or any real constraints. To be sure, there are many legitimate and highly informative blogs out there, but there are also a lot of pseudoscience blogs. How does a reader know that the blogger is legit? How do you find the signal in all the noise? (Reminds of working with fMRI data; maybe we can get Karl Friston or Robert Cox to work on an analysis package.)
A few approaches to quality control exist already. For example ResearchBlogging.org restricts its posts to serious commentary on peer-reviewed research. Potential bloggers have to register with/apply to ResearchBlogging and get approved for inclusion (TalkingBrains is a registered blog on this site), and in general this has worked well. Some academic institutions have recognized the power of blogs and have institutionalized blogging, in one form or another, within their academic community. Standford's Blog Directory is one example.
A recently published article by Batts et al. (2008) in PLoS Biology provides an interesting discussion of the role of blogging in academia, as well as some examples and ideas about how to provide quality and control and ultimately "bridge the gap between blogs and the academy." It's worth a look.
Shelley A. Batts, Nicholas J. Anthis, Tara C. Smith (2008). Advancing Science through Conversations: Bridging the Gap between Blogs and the Academy PLoS Biology, 6 (9) DOI: 10.1371/journal.pbio.0060240