In reply to andyathome:
Actually it was a bit more aggro than that. They were being fairly rude about the book and Joe as an author (in typical teenager fasion) which lead to the banter that the papers picked up on. Joe wasn't making a fuss though, he was just responding in kind.
Then a couple of them started trying to get #PervySimpson trending in a campaign to smear him as a paedophile and he understandably lost patience with it. Other people on twitter did some digging and reported the kids to their headmaster and it all went very quiet very quickly, with some of the kids accounts being deleted.
I follow Joe on Twitter and saw it all happen 'live'.. it's weird to be watching the teacup before the storm arrives for once!
It was massively overblown, but to be fair to Joe and corect the impression from andyathome's post, he was not overreacting at any point.