A good blog will inform, entertain, link, teach, be focused, have passion, photography, visuals.
Blogs could enhance an existing school website by giving people an opportunity to learn about programs, news and events. It could also be a way for the school's "customers" to be involved.
A woman I know self-published a book recently. It has taken her a year or more to write it, have it edited and find a printer. Now she has to find an audience to purchase it. Do I think blogs are an easier way for people to self-publish? You bet!
Web 2.0 is essential to learning in the 21st Century. My students use Blackboard for daily announcements, lessons (pdf files / Jing demo videos / soon to be added podcasts), communication with me and other students, submission of assignments. I am planning on incorporating more as I learn. I am fortunate to teach a computer class where students have daily access. My "classroom" now has accessibility to my students on their schedule.