ergophobe - 5:39 pm on Nov 5, 2009 (gmt 0)

One thing about Drupal is it is dead easy to create, say, hundreds of student blogs or blogs for each teacher and so on, all running under one domain. At it's roots, it was designed to connect university students to each other (it's progressed a long ways since then, though)

Another option might be WordpressMU as well.

Head on over to OpensourceCMS and you can test drive dozens of CMS and see which ones meet your needs. The only issue with that is that Drupal tries to keep required core modules to a minimum, so you don't get a sense of what it's like with more of them (in partcular file manager ones) flipped on.