Speaking as someone from a conservative Protestant background, I'm saddened when Christians view the internet as a dangerous place before they've even experienced it, thinking only of the stories of children seduced by perverts that make it into the papers. Tragedies like that happen without the aid of technology. (Not at all saying that you feel that way, CT -- just experience I've had with some)
I'm not crazy enough to think that the boy will never see a nude photo on the internet (or anywhere else, for that matter), but I would never let a computer program do my parenting for me. I'd rather do my best to be aware of what he is learning about life, look at it with him, and be there to answer his honest questions. As far as online smut, people find what they seek out on the internet, as they do in other parts of life. I expect my son to learn to use good judgment in his online life, just as he needs to in the rest of his life.