In recent decades, Sesame Street has faced societal and economic challenges, including changes in the viewing habits of young children, more competition from other shows, the development of cable television and a drop in ratings. After the turn of the 21st century, the show made major structural adaptations, including changing its traditional magazine format to a narrative format. Because of the popularity of the Muppet Elmo, the show incorporated a popular segment known as "Elmo's World".