This functionality was modified in an update. For more information, see Using the Pinboard (modified in an update).
You can bookmark your favorite objects by adding them to a list in your Pinboard, where they can be easily managed and recalled for future use.
You access your pinned items by selecting Pins 
in the sidebar to open the Pins menu, and see all your pinned items in the Pinboard. For more information, see Using the Pinboard.
When you create a new object, it is automatically added to New Items in the Pins menu. However, new objects must be added to a list in the Pinboard to save them, as they are only available in a single session.