NEW YORK (AP) — Despite all the worries about online bullying, more than two-thirds of teenagers on social-networking sites say their peers are mostly kind, a new study from the Pew Internet and American Life Project finds.

Still, 15 percent say they have been the target of mean or cruel behavior, and 88 percent say they have witnessed such behavior directed at others.

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The study, released Wednesday, also found that about 40 percent of parents of teens have friended their children on a social-networking site. But that tends to lead to more conflicts between parent and child over an experience on such sites.

The study's co-author, Mary Madden, notes that children can present a limited profile to their parents and use private messaging channels to engage with friends.

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