Shortcuts allow you to easily access the People under that Tag. You can only add Shortcuts to the Custom Tags you create. Adding a Shortcut means that Tag will now appear in the People menu.
Click on the People tab at the top of the page.
That will open the People menu.
Tags come in different colors:
Blue = Status
Green = Most promising generated lead
Black = Descriptive, Geo, and Custom
Your Shortcut Tags will appear in Black.