Thanks. As a members site it has 2 sides a front facing non-members site as seen, and if you join then there are added facilities.
modules can be bolted on, such as journals, message boards, guestbooks... have a look at postnuke.com. A lot of these are free. The site can also be themed... plenty of varieties.
Like most CMS's it gives the possibility of a complex site with little technical knowledge. Inbuilt are permissions systems as well
It's my brothers site, and he's no tecky. I do that.
S