Example:

To illustrate this concept, let's imagine a family of people living in the suburb community of Saint Charles.

The City Council of Saint Charles are users of DayKeep, and many people in this community also use this application.  Sally Smith, a highschooler in Saint Charles, along with her friends have adopted DayKeep to keep their busy social schedules in check. So, Sally has set her DayKeep up to subscribe to several groups she is interested in: The Saint Charles city, her high school, her high school band (of which she plays the trombone), a group created by her circle of friends and finally, her family's.

A traditional calendar would allow Sally to enter all the events which she finds important to her, so she doesn't miss anything.  DayKeep takes some of that work out of her hands.  For example, her father logs on to his DayKeep account (with his own set of groups, of course) and creates an event for Sally's family: Dinner on Thursday.  Sally's band instructor provides each practice day and performance day on the high school band calendar.  The city of Saint Charles advertises yet another craft show downtown on it's calendar.  And finally, Lisa, her friend, has scheduled a study session for next Wednesday.  Sally's calendar now has her calendar filled with events that she is interested in, and she didn't have to type a thing.

What's more, these events are all shared only with the people who wish to see them.  Sally's friends don't see when she's got dinner with her family, but they all know about the study session.  Sally's father doesn't know about Sally's study session, but he does see that his favorite Jazz band is playing next Friday (Sally's father, being a big jazz fan, has joined the local jazz club who also use DayKeep).

This example is pretty focused on the calendar, but one could also imagine how the group-based Contact List would work in a similar way.  Sally's contact list contains Band members, family members and all of Sally's friends.