Zynga's social resource game CityVille, which last week became Facebook's biggest-ever game, has now exceeded 100 million monthly active users. Zynga's first simultaneous international release, the game debuted with English, German, Italian, Spanish and French versions - more than half of it's current users are from outside of the US.
According to Inside Social Games, just under 19 million of this total equate to daily players. The game has a 'stickiness' (daily audience divided by monthly) of just 19 per cent compared to FarmVille's current 26 per cent, suggesting that its rapid growth is not necessarily coupled to the same long-term player retention that Zynga's farming title enjoyed.
FarmVille peaked at 84 million MAUs in March last year prior to changes made to way social games could promote themselves. CityVille is expected to reach 110 million MAUs at its peak.