Teens told researchers there were too many adults on Facebook and too much sharing of teenage angst and inane details like what a friend ate for dinner.
"The key is that there are fewer adults, fewer parents and just simply less complexity and less drama," said Amanda Lenhart of the Pew Research Center, one of the study's authors. "They still have their Facebook profiles, but they spend less time on them and move to places like Twitter, Instagram and Tumblr."
In the poll, 94 percent of teens who are social media users have a profile on Facebook - flat from the previous year. Twenty-six percent of teen social media users were on Twitter. That's more than double the figure in 2011 of 12 percent.
In what is likely a concern to parents, more than 60 percent of the teens with Twitter accounts said their tweets were public, meaning anyone on Twitter - friend, foe or stranger - can see what they write and publish. About one-quarter of kids said their tweets were private and 12 percent said they did not know whether their tweets were public or private.
Teens are also sharing much more than in the past.
More than 90 percent of teen social media users said they have posted a picture of themselves - up from 79 percent in 2006. Seven in ten disclose the city or town where they live, up from about 60 percent over the same time period. And 20 percent disclose their cell phone number - up sharply from a mere two percent in 2006.
At the same time, teens say they've taken steps to protect their reputations and mask information they don't want others to know. For example, nearly three-quarters of teen social media users have deleted people from their networks or friends list.
The researchers surveyed 802 parents and their 802 teens. The poll was conducted between July 26 and September 30, 2012, on landline and cell phones. The margin of error for the full sample is plus or minus 4.5 percentage points.