Some in my AP community are exploring the question of computers for toddlers and young children. I offered our experience:
When K was very small we let him play on the keyboard and used it to teach him letters, symbols by allowing him type with the font size very large etc. Then at about 18 months or so we discontinued pretty much all computer use for him. No computer was a follow-on to our overall no-media choice which we made because we felt it was better for his developing brain.
No-media has not been a simple choice...definitely the road-less-traveled in our culture and more and more difficult as he has gotten older and friends now have gameboys, X-boxes, computers, tv's in their cars etc etc. About two months ago, as part of our homeschooling year, we got him his own computer, two months before his 8th birthday. Right now he has free access to it, however the content on it is highly limited, currently a typing program, Rosetta Stone Spanish, wikipedia, a NASA site, Adobe illustrator, Photoshop, Paint, and Myst (the only thing that is anything like a video game but is really more like a world than a game). Yes, he wants to play more games and more often than he generally is allowed...he will ask for example to play the skiing game on my phone, for example. But he also knows that it's not our family culture to sit playing video games etc., that we regard the computer as a tool for thinking and creating etc., just like he has known for many years that our particular family culture doesn't include tv-watching. Will he become obsessed with media as a teenager or adult? Maybe...but for the first almost 8 years of his life he spent his hours playing imagination games, reading, building things, making up scenarios, reading some more, creating etc. etc.
I am extremely happy that we pushed back for as long as we did! I feel a little sad to see how much he (like probably many of us adults, myself included) now automatically gravitates first to the computer. It seems much more difficult for him to think of interesting things to do on his own now, just two months later, whereas even up until a month ago he used to be extremely self-sufficient and able to entertain himself for hours during all kinds of different things. I can't help but think that if he had had much earlier access to the computer, he likely would have missed reading hundreds of books (some many times over) and so many hours of self-created innocent play.