YouTube – Wildly successful but often lit up by controversy, the video-sharing site has its pros and cons. Lesley Stahl talks to its CEO, Susan Wojcicki, about its policies.Unsheltered – Seattle, Washington is one of the fastest-growing cities in America and one where the homeless crisis is among the most visible. Anderson Cooper goes there to report on how one city is dealing with what has become a national problem.Built by Angels – Ethiopian pilgrims have been trekking to this mysterious holy site for centuries to visit its rock-hewn churches carved out of the African plateau. Scott Pelley made the trip in time for the Ethiopian Orthodox Christmas vigil and tells this remarkable story.