(CNN) -- More than half of all teens and young adults say they have been bullied or harassed online, according to the results of a new poll on Internet behavior.
In an Associated Press/MTV poll, 56 percent of respondents, who were between 14 and 24 years old, said they had "experienced abuse" through digital media.
That's up from 50 percent in a similar 2009 survey.
Some of the most common forms of harassment include posting something online that's not true, writing things online that are "mean" and sharing texts or other messages that were meant to stay private, according to the results.
And while the ability to stay anonymous online is often cited as a reason why digital bullying can get so bad, survey respondents said that, more often than not, that's not the case.
"Most say the perpetrators of the bad behavior are people they know very well," the survey reads.
One out of three resopndents also said they've taken part in so-called "sexting," which includes sending and receiving nude photos or video or sexually charged text. Seventy-one percent of them said that "sexting" is a problem for Web users their age.
Ten percent of respondents who said they'd exchanged sexual messages said they'd done so with people they only know online -- a steep drop from the 29 percent who said they'd done so in 2009.
If there's a bright spot, it's that more respondents this year said they recognize online bullying as a problem than did two years ago and more said they'd intervene if they saw it happening.
Fifty-six percent said they would likely intervene if they saw someone being harassed online, compared with 47 percent in 2009.
The survey is part of MTV's "A Thin LIne," campaign, a multiyear effort to stamp out digital abuse.
"The campaign is built on the understanding that there's a 'thin line' between what may begin as a harmless joke and something that could end up having a serious impact on you or someone else," MTV writes on the campaign's website. "We know no generation has ever had to deal with this, so we want to partner with you to help figure it out."
The survey results were based on interviews of 1,355 teens and young adults conducted between August 18-31. It has a margin of error of 3.8 percent.