User blog comment:TheTobarMethod/ADC Mid....It can work!/@comment-98.225.114.2-20130129083606

Couple reasons for this, one being that the distance you have to cover from tower to tower in mid lane is much shorter, and since AD carries are not bursty most of the time, it would be rather difficult for them to get kills before their target could retreat to safety. Also, mid lane is expected to gank both bot and top, and AD carries typically aren't amazing at ganking.