You can boil it down a lot more than that. And not necessarily to such noble criteria.
http://www.jwz.org/doc/groupware.html famously boils it down to one question: Your "use case" should be, there's a 22 year old college student living in the dorms. How will this software get him laid?
http://www.jwz.org/doc/groupware.html famously boils it down to one question: Your "use case" should be, there's a 22 year old college student living in the dorms. How will this software get him laid?