For the uninitiated, that is the Farmville market screen where you can buy stuff. As you can see, in the top left hand corner, the rather spiffy tractor is only available to people on a certain level in Mafia Wars. Interesting.
(Those that have noticed that you can buy it without having played Mafia Wars obviously have lives. The note-type of cash is in short supply and you kind of have to spend real money on it, unlike the coin-type cash which is the games point system.)