Whether you are sitting around the same table in the library or scattered across the country, group projects often require all participants to edit the same document. These tools allow synchronous or asynchronous editing. All tools listed here are free (in general or to Virginia Tech affiliates).
All Virginia Tech affiliates have access to Google Apps for Education through VT Google Apps Portal (you can also access Google Docs through your VT Gmail account). It's very easy to share documents, spreadsheets, and presentations you create; once shared, all participants can simultaneously edit the document. You can use Google's built-in chat function to have a group chat while viewing the document.
Technology-enhanced Learning and Online Strategies provides free blogs using the WordPress platform. A common strategy for classes and group blogging is for individuals to each establish their own blog, and then aggregate that into a motherblog. You can also allow multiple users to edit a single blog.