They say it takes a village and Collaborators are those people that help you with your kids.
The most obvious Collaborator would be your spouse or co-parent.
You may also invite Nannys, Grandparents and others that help out to Cubby.
When you invite a Collaborator you can give custom access on a Cubby-by-Cubby basis. These permissions are:
View = Can View the Cubby
Email = email is filtered for this Cubby
Calendar = can add/edit calendar events,
Adm = Can administer the Family