I've been looking at setting up a blog environment for a group of students. WordPress was my initial choice, as I'm using it myself & am very familiar with it.
However, I've started looking at Elgg, (www.elgg.net). One of the things that I particularly like about that is the fact that users can define groups of friends, and then say which group each post is visible to.
As I want students to use the blogs primarily as a reflective tool, while they are working, I think that the ability to define an audience can be useful.
I've had a hunt through the plugins, and though I've found a couple (postlevels, Angsuman's Authenticated WordPress Plugin ), from what I can tell, both of them just allow you to have some posts that are open to a group of users, but you can only have one group, not multiple.
Is there a plugin that I've not yet found that does what I'd like?