I was the target of a lot of bullying by girls in elementary school, starting more or less the day I showed up. I tried a lot of things to deal with it, including spending as much time in the library during recess as I could, but all the teachers were trying to get me to play with other kids. It was insane. This was at a school where instead of A-F grades, report cards had went on a scale of plus, check plus, check, check minus, minus, as if this somehow could not be immediately translated into the letter equivalents. As is I suspect still typical of elementary schools, there were an insane number of line items on the report card as well, and I consistently got minuses in handwriting and plays well with others -- which meant the teachers were piling on, and then when I got home, my parents piled on to (somewhat -- they mostly didn't care about whether we had friends). Dead loss all around.
I did play with the boys, to avoid the girls, which worked until the boys started to care what the girls thought, and then the girls would tell less-popular boys to pick on people like me to score points. Being the person I am, I just asked them why boys who had always been friends before why they would do something rotten (like trip me), and boys being boys, they (shamefaced) told me.
Things got a little better in 3rd grade, partly because of the nature of the classroom I was in that year, and partly because I was spending part of the week at another school for a special program. They didn't really improve until 6th grade, when my school was closed and we were sent to a different school. The shake-up and increase in class size dramatically reduced the power of the ruling clique of girls, and no one else set up a stable hierarchy. Junior high and high school all had multiple groups to choose from, and it was just easier to avoid people with 6 classes a day, exterior entrances to classrooms and exterior lockers.
Tempting as it is to make fun of this article for implying that things happening at this age is new, I can't bring myself to do it. Hooray that the issue is being brought out into the open. The next step, of course, is to force the parents of the kids doing the bullying to be aware of what their children are doing and to apply some group pressure on those parents to modify their own family dynamic and personal values to a less vicious approach to human relationships.