13th place is acquired by LinkedIn.com, founded in December 2002 and launched on May 5, 2003. LinkedIn is mainly used for professional networking and as of 2013 Linkedin reports more than 259 million users in more than 200 countries and territories.

A mobile version of the site was launched in February 2008, which gives access to a reduced feature set over a mobile phone. The mobile service is available in six languages: Chinese, English, French, German, Japanese and Spanish.

On July 23, 2013 LinkedIn announced their Sponsored Updates ad service. Individuals and companies can now pay a fee to have LinkedIn sponsor their content and spread it to their user base. This is a common way for social media sites such as LinkedIn to generate revenue.