Most US teenagers who use social networking sites say their peers are "mostly kind" to one another online although the vast majority have witnessed mean or cruel behavior, a study said Wednesday.
The study by the Pew Research Center's Internet & American Life Project, the Family Online Safety Institute and Cable in the Classroom takes an in-depth look at the environment and behavior of American teenagers on social networks.
According to the study, 95 percent of US teens aged 12-17 are online and 80 percent of connected teens use social networking sites such as Facebook or Myspace.
Sixty-nine percent of the teenagers who use social networks said they are mostly kind spaces, while 20 percent said their peers are mostly unkind online and 11 percent said "it depends."
Eighty-eight percent said they have witnessed mean or cruel behavior online and 15 percent said they have personally been the target of mean or cruel behavior on social networks in the past 12 months.
Twelve percent said they witnessed cruel behavior on social networking sites "frequently," 29 percent said they encountered it "sometimes" and 47 percent said it was just "once in a while."
"Social networking sites have created new spaces for teens to interact and they witness a mixture of altruism and cruelty on those sites," said the Pew Research Center's Amanda Lenhart.
"For most teens, these are exciting and rewarding spaces," said Lenhart, lead author of the report, "Teens, Kindness and Cruelty on Social Network Sites: How American teens navigate the new world of 'digital citizenship.'"
"But the majority have also seen a darker side," she said. ""And for a subset of teens, the world of social media isn't a pretty place because it presents a climate of drama and mean behavior."
Ninety percent of teens said they ignored the mean behavior they witnessed, 80 percent said they personally defended a victim and 21 percent said they personally took part in the harassment of others on a social network site.
Nineteen percent said they have experienced bullying in the past 12 months -- either in person, by text message, by phone call or online.
Twelve percent said they were bullied in person, nine percent said they were bullied by text message and eight percent said they were bullied online, either by email, on a social network site or through instant messaging.
While 78 percent of teens said their social media interactions resulted in a positive outcome -- such as deepening a friendship -- 41 percent reported at least one negative outcome such as an argument, loss of a friendship, problems with their parents or even a physical fight.
Parents are the top source of advice to teens on online issues, according to the study.
Eighty-six percent of online teens said they have received advice from their parents about using the Internet safely and 70 percent said they have received advice from a teacher or another adult at school.
Sixty-one percent of teens said their parents have checked their social network site profile.
Nicky Jackson Colaco, who manages online safety programs at Facebook -- the world's largest social network, with more than 800 million members -- welcomed the report.
"We believe that educating teens about safety is a responsibility shared by policy makers, safety advocates, parents and services like Facebook," she said.
"Facebook believes in addressing safety, bullying and harassment issues proactively -- because building a trusted environment is fundamental to our mission and to ensuring a positive experience for people who use our site."
The survey of 799 teens was conducted April 19-July 14 and has a margin of error of plus or minus five percentage points.
Members of the Family Online Safety Institute include AOL, Comcast, Disney, Facebook, France Telecom, Google, Microsoft, Verizon and Yahoo!
Cable in the Classroom is the the national education foundation of the US cable television industry.
Explore further: Half of US adults using social networks: survey