Farm-themed games were already common even before these two Facebook apps existed. My favorite was the "Flower City Garden" where a player starts from a very small farm with simple flower plantation. The game progresses as the player sells perfectly grown flowers using the right fertilizer. Another farming-themed game I played is the "Funky Farm" where there are already plants and moving animals involved.
For me, Facebook is famous for its third-party applications and became even more famous when a company developer "Slashkey" developed the game "Farm Town". Running in an Adobe Flash platform, this game is not just a one-man-game but rather, a multiplayer online game. A gamer can also chat to other online users while playing.
Screenshot of my farm with a small house and potato seeds planted at the plowed soil.
Other online users can be hired to work in your farm.
Another similar game in facebook app is "Farmville". The game is still online only that you cannot see other online users playing. I still love to play this game because it has better graphics than "Farm Town". The two applications are more or less related in terms of features.
These two games just show how powerful and flexible flash games are. Before, Flash software is just an application used to animate things that will be embedded in a website, but now, flash has a wide range of capabilities.