There's a report on children's use of the net, safety and awareness, published this year in Norway. The report and summary is in Norwegian, but SAFT, Safety Awareness Fact Tools is an international European consortium working to increase awareness of good and safe internet use.
The study reports that more children have been harassed online and had more unpleasant meetings with other people they first got in touch with online than in 2003. It also shows an increase in net use for communication. Boys have been harassed more than girls, something which may have a connection to the fact that boys use the net more for chatting and games than girls do. Of the people reporting unpleasant meetings with strangers after netchat, the majority already had dysfunctional relationships to parents, friends or other in close relationships, a sad mirror of an adult reality where victims attract further abuse.
On the up side, children are more careful about giving out their physical address or other information which can be used to track them. They also have more email addresses, which can be used to cover their identity in online communication, and they are increasingly suspicious to information they get online. They use the net for homework, and are aware that they need to check on their information.