If you work with volunteers, you may want a way to quickly see which volunteers have signed up for shifts or events. If you're using event signups to allow volunteers to signup for events, you can open an event to see the list of signups in the event editor. This is a great approach if you're working with a large group of volunteers.
If you're working with a small group of regular volunteers, you can use a pre-populated user field and Table view to see who's signed up without opening up individual events.