Facebook, the largest social networking service, was launched in February 2004 by Mark Zuckerberg with his college roommates and fellow students. Facebook membership was initially limited to Harvard students but currently has more than 800 million users worldwide. It offers services for free and available in 70 languages. A study ranked Facebook as the most used social network in January 2009. Despite being a popular social network, many users aren’t aware of Facebook’s basic features. Here are the main features every user should be accustomed to.