Kids don't watch porn and go "IM GOING TO DO THAT"! If you are 6 or 7 years old you most likely don't know what sex is, what it is for, and you don't even understand what is going on. Not to mention most people who find porn, are looking for it. If theres a 7 year old, and he wants to play neopets, he will go to neopets.com, play neopets, enjoy his Disco Shoyru, play their mini games, etc. People don't just get popups for SEX SEX SEX PORN PORN in these child areas. If he is looking up cheat codes and he types the phrase "Super Smash Bros Brawl cheats or codes" into google, the first, second, nor 50th link isn't going to be "sexyboobsnudewomen.com" or anything like that.
At any rate, even if a child does see it, it doesn't mean they are going to do it. I have friends who watch porn, they are 16, and they are virgins. 16, they are at an age where it isn't too uncommon to have sex, as they are in their junior year of high school. At the same rate, how on earth would a 7 year old try to have sex? Even if he could see, comprehend, understand what was going on, etc. when watching his first porn by accident or intentional, that doesn't mean he has the opportunity or ability to have sex! I can guarantee a large portion of the people who are posting in this thread have watched porn before, or maybe still watches porn, and ARE VIRGINS. Not even by discipline or choice, they just don't have another companion for it. Because even if 8 year old Billy accidentally see's, understands, porn, etc. It doesn't mean he can get Donna or Heather, 8 year old girls, to also see, understand, willing to do, sex. Especially since how rare it is to even see man and woman talking or being friends at that age. How on earth is Billy going to get another 8 year old girl to take off her clothes, and put his *censored* in her *censored*? It's NOT going to happen. The girl is going to say eww gross, or something, or they won't even talk about it.
Summary: Porn isn't an issue.