Seriously, using the internet/computers should be treated with the same level of caution as grown-up scissors or fillet knives; powerful tools, but they need training to avoid hurting yourself with them. If this is what you're worried about, why are you even giving them a small computer in the first place? Your kids will always be more cunning than your security policy (a hard pill to swallow for HN users), so control their access to technology unless you're ready to have a serious sit-down discussion about the internet, personal privacy, and all that jazz. Put yourself in their shoes; if you're given a small black brick with an indeterminate number of capabilities, wouldn't your response be pushing it as far as it can go? I know that was my reaction when I was a kid, after buying a Pentium desktop at a garage sale.