The Winter Olympic Games have evolved since their inception. Sports and disciplines have been added and some of them, such as Alpine skiing, luge, short track speed skating, freestyle skiing, skeleton, and snowboarding, have earned a permanent spot on the Olympic programme. Some others, including curling and bobsleigh, have been discontinued and later reintroduced; others have been permanently discontinued, such as military patrol, though the modern Winter Olympic sport of biathlon is descended from it. [nb 2] Still others, such as speed skiing, bandy and skijoring, were demonstration sports but never incorporated as Olympic sports. The rise of television as a global medium for communication enhanced the profile of the Games. It generated income via the sale of broadcast rights and advertising, which has become lucrative for the IOC. This allowed outside interests, such as television companies and corporate sponsors, to exert influence. The IOC has had to address numerous criticisms over the decades like internal scandals, the use of performance-enhancing drugs by Winter Olympians, as well as a political boycott of the Winter Olympic Games. Countries have used the Winter Olympic Games as well as the Summer Olympic Games to proclaim the superiority of their political systems.