Facebook has removed a restriction for users under 18 that previously limited who could see their online postings from photos to musings on the world-wide social network.
The social network said that teenagers would now be able to manually alter the setting and share information with the public.
Until now, a teenager's postings on Facebook were only viewable to their friends, and to the friends of their friends.
However, Facebook said the default setting when teens do share information on the 1.15 billion user network would go out to a narrower group of people.
"Teens are among the savviest people using of social media, and whether it comes to civic engagement, activism, or their thoughts on a new movie, they want to be heard," Facebook said in an announcement of the changes.
"While only a small fraction of teens using Facebook might choose to post publicly, this update now gives them the choice to share more broadly, just like on other social media services," the company said.
The change comes as Facebook faces increasing competition from a new crop of mobile and social services, such as SnapChat and WhatsApp, that have proven popular with younger users.
Jeffrey Chester, Executive Director of the non-profit Center for Digital Democracy, said that Facebook was sacrificing the safety and privacy of teenage users in order to further its business.
"Teens don't necessarily have good judgment and to the extent that they make themselves visible to the wider public, there's all kind of people - from predators to junk food marketers - who are surveilling Facebook for new kinds of targets," Ms Chester said.
Other social media services also allow teens to share information with the broader public. But Ms Chester noted that the amount of personal information that users have on Facebook is far more extensive than on other social services, where users can create accounts with pseudonyms.
Facebook said that teenage users will also now be allowed to use the "Follow" feature, which lets strangers automatically receive public posts from another user without requiring that the two be connected on the service as mutual "friends."
Nicky Jackson Colaco, Facebook's manager of privacy and public policy, said that the changes would allow teenagers to share information that might benefit from dissemination to a broader audience, such as information about fundraising efforts, or a teen rock band trying to promote an upcoming performance.
Malala Yousafzai, the 16-year-old Pakistani activist, would not have been able to use Facebook as a broad communication channel under the previous policy, noted Stephen Balkam, of the Family Online Safety Institute, a non-profit that receives funding from several Internet companies, including Facebook.
Facebook said it would show teenage users a special notice the first couple of times they attempt to post information to the public, reminding the user that the post can be seen by anyone.
The restrictions on teen use of Facebook's private messaging feature will not change, with users under 18 only able to receive messages from their friends and from the friends of their friends.