Some kids suffer both in-person and electronic harassment, but it's more often one or the other.
Many were easily handled by deleting the comment or blocking additional postings from the sender.
Police say Saari, dressed in black and carrying a large bag, entered the school around 11 a.
I was scared to death.
The Transport Safety Administration said the man was unarmed and had been screened before getting on board the flight.
A gunman who killed 10 people at a school in Finland wrote handwritten notes saying he hated humankind, and that he had been planning the attack since 2002.
Ybarra's survey asked not only whether someone made aggressive or threatening comments, but also whether someone had made rude or mean comments or spread rumours about them.
Saari had also left violent YouTube postings and police had questioned him about the videos just one day before the attack.