There are obviously boundaries as to who should view what, but these boundaries are extremely unclear. Parameters are in place to try and prevent children from viewing such things, but these are easily bypass-able. For example, the security on YouTube allows for videos to be flagged by users if deemed inappropriate. If flagged, the video will then only be viewable by people 18 or older, and if it's continually flagged then the video will be taken down. But the obvious error in this is that anyone of any age can make an account saying they're 18 and then be able to view these videos.
At the same time, children have different levels of maturity. A child who grew up in the suburbs would have a different level of maturity and a different state of mind than someone who grew up in the ghetto. Children have different levels of maturity and different ideas of what's acceptable. This is usually instilled by parents as well. An old friend of mine grew up believing that the word for fart was "Phanny Burp." He believed this until he was 14 because his mother thought that fart was a bad word. Should he have been censored? is fart a bad word? was it fair to keep him from knowing "bad words" and resulting in him being mocked, teased, and bullied in school for using words and phrases like "phanny burp?"
Censorship is different for everyone, and usually controlled by parents. I know the first time I saw a pg13 movie, i was 11 and it was Pirates of the Caribbean. My friend who i was watching it with had already seen several pg13 and R movies, though she was the same age as me. She was also much more mature and could handle it while i had nightmares about the undead pirate haunting me for weeks to come. The age of consent all depends on the mentality of the child, their maturity because i know people my age now who are too fragile to see something like a sex scene or violence in Lord of the Rings, whereas other people my age are totally into that kind of thing and enjoy it. People would say about my fragile friend, "She's seventeen, she can handle it," but can she? if we were all 5 or 6 years younger, they'd be praising her for her goodness ad scolding my more "mature" friend for being exposed to this at such a young age. There is no specific age, it all depends on the maturity and mental state of the person. This usually is affected by parenting, schooling, the general environment in which a child is raised.
I guess the answer to this question depends on how you categorize children. I could respond to that question with a broad, general answer, but since I operate on the principal that everyone is an individual, and deserves to be treated as such, I will refrain from doing so. Some people obviously mature faster than others, and that maturity should grant them certain privileges. Although our society does not operate on an individual basis, I believe that for anyone under 18, consent to view certain types of media should be a decision regulated in the home, not by the government. If a parent and child can reach a consensus regarding what kind of media the child can watch, and that particular child is 12 years old and his parents let him watch Quentin Tarantino or what have you, then so be it. I am not a parent, and therefore do not possess the necessary perspective to comment on what others choose to allow their children to do or see. Obviously the internet presents a certain degree of anonymity, and allows underage individuals to be older in cyberspace in order to access certain content. I personally do not have the desire or time to dictate what people do with their lives, and if a 16 year old kid wants to watch porn on his laptop, then that is none of my business. I could get into the whole "media violence is ruining our society" debate, but I will stick to my general philosophy of letting people be as they are, unless they are directly endangering themselves or others.
