My Content is your personal library where you can store your favorite material.
My Content has two sections. In the first section, you have access to items previously stored as Favorites. This can be images, diagrams, or perhaps the full presentation to reuse in other prezis. In the other section, you have access to frames from all prezis that you previously created.
Reusing good material is a great option because it saves you from recreating similar items over and over again. Even if you need the item slightly altered, it is often quicker to rework or alter an existing design than to create an element from scratch.