Candy Crush Saga was first released on Facebook in 2012.
King launched the Facebook version in April 2012, initially with 65 levels. It was based on an earlier Candy Crush browser game and incorporated the level-by-level “Saga” structure that King had developed for games such as Bubble Witch Saga.
The year is sometimes confused with 2011, when the original Candy Crush portal game appeared, or with 2012 mobile releases. The iOS and Android versions followed later in 2012, helping the game spread far beyond Facebook. By January 2013, Candy Crush Saga had become the most-played game on Facebook, overtaking Zynga’s FarmVille 2.
That launch sequence matters: 2011 refers to the earlier web game, while 2012 marks the release of Candy Crush Saga as the Facebook social game named in the question.