Facebook is an online social networking service. Its name stems from the colloquial name for the book given to students at the start of the academic year by some American university administrations to help students get to know each other. Facebook was founded in February 2004 by Mark Zuckerberg with his college roommates and fellow Harvard University students Eduardo Saverin, Andrew McCollum, Dustin Moskovitz and Chris Hughes. The website's membership was initially limited by the founders to Harvard students, but was expanded to other colleges in the Boston area, the Ivy League, and Stanford University. It gradually added support for students at various other universities before opening to high school students, and eventually to anyone aged 13 and over.
Users must register before using the site, after which they may create a personal profile, add other users as friends, exchange messages, and receive automatic notifications when they update their profile. Additionally, users may join common-interest user groups, organized by workplace, school or college, or other characteristics, and categorize their friends into lists such as "People from Work" or "Close Friends". As of September 2012, Facebook has over one billion active users, of which 8.7% are fake. According to a May 2011 Consumer Reports survey, there are 7.5 million children under 13 with accounts and 5 million under 10, violating the site's terms of service. Facebook (as of 2012) has about 180 petabytes of data a year and grows by over half a petabyte every 24 hours.
By January 2009, Facebook ranked as the most used social networking service by worldwide monthly active users. Entertainment Weekly included the site on its end-of-the-decade "best-of" list, saying, "How on earth did we stalk our exes, remember our co-workers' birthdays, bug our friends, and play a rousing game of Scrabulous before Facebook?" Facebook eventually filed for an initial public offering in 2010 and began selling stock to the public on May 18, 2012 (NASDAQ). Based on its 2012 income of $5.1 Billion, Facebook joined the Fortune 500 list for the first time, being placed at position of 462 on the list published in May 2013.
Most of Facebook's revenue comes from advertising (revenues estimated, in millions):
Year Revenue Growth
2007 $150 188%
2008 $280 87%
2009 $775 177%
2010 $2,000 158%
2011 $4,270 114%
Facebook generally has a lower click through rate (CTR) for advertisements than most major Web sites. According to BusinessWeek.com, banner advertisements on Facebook have generally received one-fifth the number of clicks compared to those on the Web as a whole. For example, while Google users click on the first advertisement for search results an average of 8% of the time (80,000 clicks for every one million searches), Facebook’s users click on advertisements an average of 0.04% of the time (400 clicks for every one million pages). The cause of Facebook's low CTR has been attributed to younger users enabling ad blocking software and being better at ignoring advertising messages, as well as the site being used more for the purpose of social communication as opposed to viewing content.
However, a study found that, for video advertisements on Facebook, over 40% of users who viewed the videos viewed the entire video, while the industry average was 25% for in-banner video ads.