Twitter is booming as a social media destination for American teenagers who complain about too many adults and too much drama on Facebook, according to a new study about online behaviour.

It says teens are sharing more personal information about themselves, even as they try to protect their online reputations.

"The key is that there are fewer adults, fewer parents and just simply less complexity," said Amanda Lenhart of the Pew Research Centre, 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% of teens who are social media users have a profile on Facebook - flat from the previous year. Twenty-six per cent of teenage social media users were on Twitter, more than double the figure in 2011 of 12%.

"Facebook just really seems to have more drama," said Jaime Esquivel, 16, in an interview.

He said he still checks his Facebook account daily but is not using it as regularly. Jaime sees teens complaining on Twitter, too, so he has been using the photo-sharing service Instagram more often, posting a couple of pictures each day and communicating with friends. Facebook bought Instagram last year.

In what may be a concern to parents, more than 60% of the teenagers with Twitter accounts said their tweets were public, meaning anyone on Twitter - friend, foe or stranger - can see what they write and publish. About a quarter of youngsters said their tweets were private and 12% said they did not know whether their tweets were public or private.

Teenagers are also sharing much more than in the past. More than 90% of young social media users said they have posted a picture of themselves - up from 79% in 2006, the poll said. Seven in 10 disclose the city or town where they live, up from about 60% over the same period. And 20% disclose their mobile phone number - up sharply from 2% in 2006.

The poll suggested teenagers are also taking steps to protect their reputations and mask information they do not want others to see. For example, nearly 60% of young social media users said they have deleted or edited something that they had published. Just over half the teens have deleted comments from others on their profile or account.

The researchers surveyed 802 parents and their 802 teenagers. The phone poll was conducted between July 26 and September 30 last year.