Sarah is part of an important trend in communication. Social networking sites become more and more popular every day, and they are popular all around the world. In Japan, the top site is Mixi. In Europe, it is Bebo. The most popular site in Latian America is Orkut. In the United States, the top site is Facebook. In fact, Facebook is one of the most popular social networking sites in the world. A Harvard University student started Facebook in 2004, and it spread to more than 400 million users in just a few years.