A person following the trend of technology by buying up every malfunctioning, piece of iCrap that gets put out by Apple.
Person 1: "Look at Kate with her new iPod nano."
Person 2: "But she only just got a new iPod a few months ago."
Person 1: "But now the iPod nano is the newest thing, so that old iPod is obsolete!"
Person 2: "What an iSheep."