Nelson co-founded Itty bitty machine company, or "IBM", which was a small computer retail store operating from 1977 to 1980 in Evanston, Illinois. The Itty bitty machine company was one of the few retail stores to sell the original Apple I computer. In 1978 he had a significant impact upon IBM's thinking when he outlined his vision of the potential of personal computing to the team that three years later launched the IBM PC.