LinkeIn (pronounced IPA: /ˈlɪŋktˈɪn/) is a business-oriented social networking site founded in December 2002 and launched in May 2003 mainly used for professional networking. As of December 2007, its site traffic was 3.2 million visitors per month, growing at an annual growth rate of about 485%.As of May 2008, it had more than 20 million registered users, spanning 150 industries.