You might consider using a combination of various Google services. They've been really busy developing web content services that are sort of under the radar for people who don't actively keep up with what they're doing. For instance:
Google Groups: Primarily discussion based, allows you to maintain discussions via the web interface or Email. Also supports document sharing and individualized pages for static content.
Google Documents: Might pair well with groups, allows for collaboration and shared storage of a myriad of document types, currently supporting Word-like documents, Excel-like spreadsheets, and PowerPoint-like presentations.
Google Pages: For static content delivery. A very intuitive interface for creating, editing, and publishing web content.
... not to mention the variety of other services they offer, like Calendar, Photos, and Base (databases). This suite of products and services isn't all tightly integrated yet, but I can only imagine that they're heading in that direction. If nothing else, you could tie them all together yourself by creating a page with Pages or Groups that has links to your group's Documents, Calendar, and Photos.
My own personal and casual interest in this junk aside, I've done a lot of research on content management and delivery with my company, so I'd be happy to help more if you'd like. Just PM me, and we can work something out as far as a more convenient medium for conversation is concerned.