Facebook is an online social media service and is successful.
Facebook is an American for-profit corporation and an online social media and social networking service based in Menlo Park , California . On July 13 , 2015 , Facebook became the fastest company in the Standard & Poor 's 500 Index to reach a market cap of $ 250 billion . As of April 2016 , Facebook was the most popular social networking site in the world , based on the number of active user accounts .