Feature:
- the ability to specify that all Sub-cases of a Parent Case share comments, emails and release notes. Effectively... the comments, correspondence, release notes (perhaps other attributes) are maintained in the Parent case but are seen identically and editable in all Cases of the family.

Use Cases:

- users estimate their time and book time against individual cases, but any comments or correspondence added to those cases are grouped together

- regardless of projects or milestones set in the sub cases, the customer facing release notes belong to the Parent case, its project and Milestone.

- anyone  interested in the full history of all the cases in the family can view easily in the Case they are primarily interested in

- the feature is optional... the configuration goes with all the Cases in the "Family" or none of them

Value Added:

- the benefits of improving time estimates by creating sub-cases for every role no longer need to be weighed against the disadvantage of multiple cases containing important, related content