NIAHD Journals
http://www.wm.edu/niahd/journals/
The NIAHD Journals site is, essentially, a blogging site that I developed that is customized for use in college courses. The instructor puts students into class groups and assigns entries on a given issue on particular days. The site is used by James Whittenburg of the History Department in his courses on Virginia's colonial, revolutionary, and antebellum history. These courses tend to be field-trip heavy; in their journal entries student not only reflect upon their readings, but record their thoughts about and post photos of sites of import in the history of the mid-Atlantic.
The backend of the site is programmed in PHP. The database used to store all the site's entries, photos, and other data is MySQL. The site is xhtml 1.1 strict compliant (or as least as much as I can make it--some of the students' entries contain non-xhtml compliant characters).