Major differences between the ipod touch second gen and the fourth gen. The screen on the fourth gen is so much sharper. It also can take pictures, which previous generations of ipod touches cant do. Plus it has face time which is not a feature that I need or want but for some reason my sons and daughter think its really cool to have. Im not even sure what it does on the ipod but I know that if your on the iphone you can talk and see the person your speaking to if they also have face time on there phone. Im not sure how this can be used on the ipod touch unless your using the wi fi connection and something like skype to make your phone calls.