Allowing organizations to share parts of their project data in a secure manner allows them to jointly plan and manage projects while keeping security and privacy.
For example: Software vendor <A> may have a milestone MS1 within project P1 that he would like some contractor <B> to manage for him. <A> does not wish to share all the details of project P1 with <B>, while <B> does not wish to share all the details of the plan he prepares and executes in order to deliver MS1 on time. Both project plans, of P1 and MS1, are in sync allowig both parties to work concurrently while maintaining their security and privacy.
Tagging allows users to create their own vocabulary and view how other people tagged objects in the system.
For example - a user may tag some milestone as 'design' and 'risky' tags. This will allow this user to later on search for all the objects he had tagged as 'design' or 'risky' - tasks, milestones, projects, etc.
Rating allows users to create knowledge about the quality and relevancy of objects in the system and can be used in a large variety of ways.
For example: templates can be rated to reflect whether they assist project managers in creating better project plans.
Another example that may require additional security and authorization mechanisms is to allow manager to rate the performance of users in their team or of suppliers they work with.