But wait - where's EA / Playfish's the Sims Social? The game still sits as the number five game on the service, but it has lost players (around 1.7 million) even since we threw out some advice that Playfish should try to help the game climb back up the ranks. And that was just a week ago!
Either way, does CastleVille have what it takes to finally topple CityVille as the number one game on Facebook? It still has 12.5 million more players to go (and that's if CityVille does nothing but lose between now and then). Still, it will be interesting to watch as the competition develops further (or doesn't) between these two games, and you can be sure that we'll let you know if Facebook finally receives a new king to the castle if and when that does happen.
Do you think CastleVille can take over the number one game spot on Facebook, or is CityVille still too mighty a beast to defeat? Share your thoughts with us in the comments!