50% of the players of The Sims Social are Zynga players

"Electronic Arts came out of nowhere when it launched The Sims Social on Facebook. The social game that simulates human life took off like wildfire, surpassing FarmVille and closing in on Zynga’s most popular game, CityVille. Now Raptr, the social network for gamers, has revealed some interesting data about just who is playing The Sims Social. As suspected, many of the players came from Zynga.
The majority of The Sims Social’s user base are Zynga players, according to data collected from 10 million people on Raptr’s gamer social network. EA’s own social games and The Sims 3 accounted for only 15 percent of the total players of The Sims Social. Zynga players, on the other hand, account for 50 percent of all of The Sims Social players. About 30 percent came from other social games, and 5 percent came from World of WarCraft.
The Sims Social is now the No. 2 game on Facebook with 66 million monthly active players, compared to 76 million for CityVille, according to AppData. If roughly half of those players came from Zynga, we’re talking about close to 33 million users. Of course, not every single one of the Zynga players has quit playing a Zynga game in order to play The Sims Social. But CityVille has dropped from more than 100 million players."
Source:  VentureBeat, 12th October 2011