They're often not as full-featured as standalone applications. But they should be able to control timing of projects and document creation, as well as group scheduling. This is the bread and butter of the groupware market. A groupware product should be able to set general rules to control document flow based on author and type of document. Some packages even let you draw graphical workflow diagrams that automatically regulate document handling.
Management control is key.
With large numbers of documents, you must have facilities for archiving, backup and access control. If many of your users travel or work at remote sites, this is essential. The software should make remote access seem just like working at a computer attached physically to the network. Groupware that works with a Web browser can give access to documents, but full features often are unavailable. The more seamless the interface, the easier life will be for users.