OnTime Team Wiki makes it easy to create documents that everyone on your team (with appropriate security) can edit. Team rosters, brainstorming documents, product roadmaps, and knowledge bases are great examples of documents that benefit from having one location and many authors.
Sometimes it is more desirable to comment on a document, versus editing or changing the document itself. The OnTime Team Wiki commenting system allows your team to discuss documents in the same place where they are created.