Community
The Community is the really interesting bit of CAGD. Most VLEs and LMSes and e-portfolio systems are all about the individual; CAGD is about individuals sharing things with each other. As I said earlier, the reason we built CAGD in the first place wasn't so that our students could store and retrieve files, it was so that they could see what each other was up to and get feedback from each other.
Most people will have a pre-made community when they join CAGD. For students it will be their course or their course level, for staff it will be their course or their school.
The main Community -- the one that you'll find yourself in by default is set up as a hierarchy to reflect the structure of your Real Life community, but there are many ways to structure things within CAGD. Some of the groups that make up the wider community are deeply nested with complicated hierarchies that set out the relationships between people, whereas some of them are large flat-structured groups with everyone at the same level.
Relationships between people -- and therefore the things that people can and can't do on CAGD with each other -- are defined in most cases by the groups that they belong to. For example, if you are in a tutorial group with me, and you are listed as a student when I am listed as an academic, then CAGD defines the relationship between the two of us as me being your personal tutor.
This concept can be a bit tricky, and one of the most common reasons that things don't go quite as they should is where someone has been put into the wrong group, or not been moved out of a group when they've left, or got the wrong role within a group.
One other thing to mention about the Community is that at the very top level of the CAGD group hierarchy are special groups that are self-contained Communities. If you're only in one of these then you won't notice them, but if you're in more than one then you'll see a list when you click 'Community" in the Main Menu.