More and more, celebrities are using their star power to promote causes ranging from fighting poverty and protecting the environment to safeguarding human rights and working for world peace. More than 2,800 celebrities now support slightly more than 1,800 causes. In a celebrity-obsessed society, entertainers and athletes can help focus public attention on global trouble spots, raise funds for disaster relief or increase public awareness of little-known diseases or medical conditions. The idea of looking to celebrities to educate the public about important issues may seem paradoxical, but some celebrities work hard to master difficult issues. The singer Bono has met with world leaders on global poverty issues, for example, while actor George Clooney has helped document Sudan's war against the breakaway state of South Sudan. Celebrity advocacy is likely to increase, experts say, with social media such as Facebook and Twitter increasingly used to air views, raise money and engage supporters.