Creating a place where multiple students can work on the same document or project has always been problematic. Sharing a USB memory stick or sending e-mail attachments can be limiting and risks potential loss.
Wikis are an easy way to foster group collaboration and create communities. On-line document editing sites like Google Docs allow easy, right-now collaboration.
There are a number of companies getting into the on-line document editing business. Look for ones that meet your needs and budget.
Wikis work well for historical inquiry projects.