I haven't gotten my mind fully around the taxonomy model, nodes, roles, organic groups, etc. to determine if Drupal is the CMS we're looking for our K-12 school.
I'd like the school itself to create certain sub-communities (groups) which can have their own secure content such as forums including email notification of new postings, galleries, calendars, polls, surveys, etc.. Different people in each group would have different access rights to various functions of the various modules.
It would nice, although not a requirement, if groups could be created without a central administrator getting involved, which sounds like what organic groups are designed for.
Security would need to be very tight since some groups will include the board of directors, financial aid committee, finance committee, development committee, etc.. In short, every committee would need its own community of content (awhhh). A group would need to be created for the parents of each class (K-12), as well as groups for the students of each class. At the moment these are accomplished with email lists (parents2007, students2007, etc. ) Each student club and sports team would also be a sub-community (group).
In addition, each course could be a group including the instructor and the students enrolled in that course, but now we're getting in Moodle territory and I'd have to decide whether to use Drupal alone or try to find an integration with Moodle, which seems to be adding more CMS functionality.