Skype is now in your sketch, feel free to call or video-call others when a certain condition is met.
Learn more from the examples page.
This shield is one of the communication shields.
Communication shields allow you to use your smartphone as a gateway between Arduino and other phones, they make it easier to communicate with your Arduino board by sending and receiving data to or from another phone.
Learn more from the communication shields tutorial.
Skype library allows your Arduino to make skype calls within a certain action or conditions.
Adding #define CUSTOM_SETTINGS along with #define INCLUDE_SKYPE_SHIELD is a key that will let you unlock the Skype shield only amongst all shields and prevent 1Sheeld library from eating your memory specially for UNO board.