2.LinkedInLinkedIn is a professional social networking site in the United States. It was created in December 2002 and launched in Monica, California on May 5, 2003. LinkedIn is mainly used for professional networks. As of January 2013, LinkedIn has more than 200 million users in more than 200 countries and regions. LinkedIn has English, French, German, Italian, Portuguese, Spanish, Dutch, Swedish, Romanian, Russian, Turkish, Japanese, Czech, Polish, Korean, Indonesian, Malay and other languages. According to a Quantcast report, LinkedIn has 21.4 million monthly unique visitors in the United States and 47.6 million monthly unique visitors worldwide. In June 2011, LinkedIn had 33.9 million unique visitors, a year-on-year increase of 63%, surpassing MySpace in one fell swoop. LinkedIn applied for an initial public offering in January 2011.