Finally, the security gurus took a device popular in the US, and used non-encrypted ethernet communication between the terminal and other peripherals to hack into the payment device and take root control.
So if you and a Firesheep user are in a coffee shop together taking advantage of free wireless and you visit a non-encrypted version of Facebook, the Firesheep user can hop into your account and take a look around.
Every cyber-criminal dreams about users on unsecured Wi-Fi networks, typing passwords into non-secure websites, and visiting domains that may not be encrypted.