Wow, for once I agree with most of the repliers to this thread.
Okay, first off, "...but when she didn't return till dark..." Until? Like the kid DID return? No she didn't. Maybe this whole thing is a hoax, maybe something was lost in the translation. It did happen in China.
Second, porn is obviously not behind this. Anyone with half a brain can rule out that 1) porn doesn't show things like this, and 2) exposure to stuff doesn't make you do what you've seen, especially when you're a young teen and reject almost everything anyone tells you. Additionally, exposure to porn can do nothing harmful except mar your perception of acceptable sex, but it doesn't spur you to actually do anything; it only changes the circumstances of what you WOULD do if you DID do something.
This is some crazy ass shit, though.