This growth can likely be attributed to the ability of the Facebook app to easily reach users who don’t have a smartphone, and due to the social hooks that Rovio has taken advantage of. When playing the game, its easy to invite your friends and see how you stand up next to your friends who have also played the same level. You can also “brag” to your fiends about the score you’ve gotten, and Facebook posts the points you’ve scored on your wall.
While somewhat unsurprising, this growth is still remarkable.