I'm all in favor of moving the locus of control in determining what is and is not appropriate content to be reading/viewing in school down to the level of teachers and students as much as is practical. I just don't think that making these judgments is a "literacy" skill, as Ewan's post (and others, to be sure) implies. I'd call it "propriety." Particularly regarding YouTube, there isn't much porn there, so aren't you just telling kids not to watch dogs on skateboards when they're supposed to be doing their math? Is that now "literacy?"