Protect the children?
One question I always ask people, and have never received a valid response to, is "how does nudity, erotica, or pornography harm or damage a child?" In the US, we spend a lot of time and resources trying (and usually succeeding) to convince ourselves and others that nudity and sex (and everything having to do with nudity and sex) is somehow "wrong", "immoral", and "dangerous". We go so far as throwing people in jail for having consensual sex in private if one of them happens to be 17 years old or if a 16- or 17-year-old decides to post nude pictures of themselves voluntarily.
Simply put, nudity is natural. There is really nothing more natural than nudity. It's how every single one of us came into this world. You may not like to look at everyone's nude body (especially in the US), but it's not "wrong" or "immoral". And yet many people equate "nude" with "pornography", saying that any picture of a nude woman is porn, somehow granting exceptions for pictures and statues of centuries past (any recent picture or statue is considered pornography).
Similarly, sex is natural. None of us would be here without it. Sex is necessary to the survival of the human species (whether or not you think that's a good thing), and yet we treat it as something dirty that can't be mentioned. We hide sex whenever possible in reality, while displaying it as much as possible in works of fiction (movies, TV, etc). We demean women who wear "revealing" clothing while cheering models who wear the same (or even less). We drool over the pages of the Sports Illustrated swimsuit edition, calling the models "gorgeous" and "perfect", while at the same time calling women on the streets "sluts" for displaying too much skin.
Hell, the readers of this journal are just as bad. These readers are quick to badmouth Britney Spears because she was photographed in public without wearing panties. And yet these same readers who badmouth her were (before those photos became public) likely scouring the internet to find pictures of her nude. Once word of those pictures came out, these same readers likely raced against the clock to find said pictures (after calling her a slut, of course). Hypocrisy, anyone?
Perhaps the point of this comment can best be summed up as: the more you "protect", the more you vilify; the more you "protect", the more you harm. Would we have such a problem with verbal and physical assault (including rape) against women who dare to wear revealing clothing if we were taught about sex and taught to respect sex (and women) instead of being taught that sex is something to be ashamed of and treating women as sexual objects?
Maybe we don't need better protection for children. Maybe, just maybe, it's education we need.
As for puritanical parents who do vilify sex and want to "protect" their children from it (these are usually the Christian people with 27 kids), there are already numerous solutions out there to do just that, on a per-computer basis. Or, if you have multiple computers connected through one internet connection, you can get a web-filtering application such as DansGuardian to protect all of the computers (that way, you don't have to worry about smart little Johnny disabling it on his system). Either way, the solution is already available for parents who want to do something about it. Why spend countless hours and resources reinventing the wheel and making things more inconvenient for everyone else?