Google Inc. is an American public corporation, earning revenue from advertising related to its Internet search, e-mail, online mapping, office productivity, social networking, and video sharing services as well as selling advertising-free versions of the same technologies. Google has also developed an open source web browser and a mobile operating system. The Google headquarters, the Googleplex, is located in Mountain View, California. As of March 31, 2009 (2009 -03-31)[update], the company has 19,786 full-time employees. The company is running millions of servers worldwide, which process hundreds of millions of search requests each day and about 1 petabyte of user-generated data every hour.