My kids don't get the password/pin to any machine that has internet access. When we log them in, they must be within view of others at all times. They don't use computers recreationaly most days a week.

Kids don't need computers. The internet is a cesspool filled with dysentary. They'll have to learn to navigate the cesspool someday, just like they need to learn to avoid heroin, but you don't need to teach your 4 year old not to seek out good fruit of the opium poppy. Some lessons can and should be delayed.