Fastest-growing Facebook games: From Song Pop to Dragon City

[Every other week, Gamasutra examines the fastest-growing Facebook games according to monthly active users, looking at which titles and developers are having the most success attracting new players on the social network.] Zynga's recently launched Bubble Safari continues to dominate the "puzzle bubble" genre on Facebook, and its quick growth has made the game the third largest on the social network in terms of monthly audience size, behind only CityVille and Texas HoldEm Poker. With 26 monthly active users -- 5.6 million of which just started playing in the last week -- Bubble Safari has even more players than the Draw Something app (not an actual game, but it interacts with the popular mobile titles) right now, which has only 22.2 million. Several other bubble-themed games continue to thrive, too: Peak Games's Lost Bubble, Cookapps' Buggle, and PlayQ's Bubble Blitz, though none of them are growing anywhere near the rate that Bubble Safari is enjoying. FreshPlanet's name-that-tune game Song Pop continues to pick up steam on Facebook and is the second fastest-growing title on the site at the moment, as it's more than doubled in size to 3.9 million players in the last week. Fantasy-based dragon-breeding game Dragon City, the latest from Social Empires and Social Wars developer Social Point, is also growing at a good rate -- it now has 2.3 million players (around 600,000 of them new). The full list of the top 20 fastest growing Facebook games along with exact monthly active user counts, are as follows: All charts and data are courtesy of Facebook application metrics and trends site AppData.