A couple years ago this was a thread topic I started when my sister was looking for software to keep her kids from porn sites:
Safe surfing?After much discussion and investigation the only really "safe" way to let the kids online was to put the computer that had net access in a common area that would allow parental overview. The kids could not go online unless a parent (Mom in this case) was in the room. While you can't keep them from going to a friend's house and seeing all there is out there, at least you can control your own environment.
Granted much has transpired over the last few years but I think the basics are the same.
Here's an old classic thread that discusses the idea of internet filtering in theory (including tacit's philosophy and opinion of CyberPatrol). A good read.
Internet filtering/CyberPatrol
