The munchkin is 12, and has had his own laptop since he was 10.
Part of that was because I obviously was not going to let him on my computers, due to the nature of my work.
The internet is an invaluable tool, but I explain it to him that just like I wouldn't let him loose to roam wherever he wants to in the world, I won't let him loose to roam wherever he wants to on the internet. He's only allowed to use it in the same room I am in, and I have vastly exaggerated my ability to track his activity, even if he tries to clear his tracks.
He believes me.
It comes in very, very handy for homework, and we use it to find out all sorts of stuff that I can't answer for him. ie, very recently we used it together to find out how to tie a tie, as he needed to wear one, and I had no clue how to do it.
I can understand parents being leery of it, but I believe that children need to be computer literate, and it is something best taught responsibly in the home.