Digital Doctor
Well-known member
https://www.yammer.com/product/features/content-collaboration/
Follow files - get updates when changes are made.
Real time editing.
More that one person can a Yammer Page edit at a time.
Feature Highlights
Files, Pages, Versioning, Popular Content, Full-Text Search, Ticker (Activity), Topics (Tags),
Feature List
https://www.yammer.com/product/feature-list/#content-collaboration
Seems to have everything but real time TODO management !!!