It depends how often you put him on the computer. Personally, I don't think computer usage is necessary at early ages. I used to teach computer classes at an elementary school and it seemed like a waste of time to have children below 3rd grade using computers. The children were better at playing mindless games than doing productive work and their penmanship suffered. As for my toddler, she goes on the computer once a week for about 5 minutes. I let her use the paint program to gain some fine motor skills with the mouse and I use MS Word to teach her new words.

So, point being, the computer is a useful tool if used wisely.