Google Docs can be used for live documents/team coordination.

Notes for usage:

• Those assigned with edit privileges can select text and add comments.
• Additionally, tasks can be assigned to individuals by starting a comment or comment reply with the plus sign (+) immediately followed by the email address of the assignee and then checking the check box in the prompt.
• If you view the document without opening the full comment panel, you'll see comments in the sidebar, alongside the respective sections.
• Use the full comment thread to see all comment threads by most recent activity.
• Eastern Standard strongly recommends that before a person mark a task as "resolved", that person add one more comment to the specific thread indicating what the resolution taken was.
• By default, users only receive notifications for comments/tasks they were assigned to.  Also by default, the owner of the document will receive notifications for all comment activity.