While Facebook’s announcement yesterday that teens 13-17 will now be able to join the adult masses in sharing their posts publicly is touted by the company as a way to give youngsters more choices, it probably has a lot more to do with money. When advertisers see teens, after all, they’re basically seeing piles and piles of cash futzing around on social media all day with their pals, just waiting to be marketed to.

Before now, teens up to 17 had their default privacy settings to share posts only with “Friends of Friends,” with the option to limit that to only “Friends” but not to expand it to the general public. That is all going to change, with the initial setting set on “Friends” and the sky as the limit for sharing.

“Teens are among the savviest people using social media, and whether it comes to civic engagement, activism, or their thoughts on a new movie, they want to be heard,” Facebook wrote in the blog post announcing the change. “So, starting today, people aged 13 through 17 will also have the choice to post publicly on Facebook.”

With the ability to post publicly comes the chance for marketers to see what teens are posting and then aim ads targeted directly toward them. It’s a veritable cash crop of opportunities for those advertisers and data miners, and something that could possibly concern parents worried about their children’s privacy.

And while other social media sites like Twitter and Instagram have always allowed teens to post publicly, the difference here is that Facebook accounts are created under real identities — not “KoolKidLOLz” or whatever.

To that end, it appears Facebook’s only safeguard for teens is a warning before they turn on the public sharing option. And if these kids are anything like the rest of us, what are the odds that they’re actually going to pay attention to what adults tell them?

Says Facebook: “When teens choose ‘Public’ in the audience selector, they’ll see a reminder that the post can be seen by anyone, not just people they know, with an option to change the post’s privacy.”

A definition of the word “public,” in other words, is all that stands between minors and the wide world of marketers or other potential schemesters.

The long-term consequences of posting their thoughts, likes or photos on Facebook is something teens might not really understand, Kathryn Montgomery, an American University professor of communications who has written a book about how the Internet affects children told the Associated Press.

“On the one hand, you want to encourage kids to participate in the digital world, but they are not always very wise about how they do it,” she says. “Teens tend to take more risks and don’t always understand the consequences of their behavior.”

Parents, talk to your children. Tell them that while it might seem fine to tell the entire Internet world how bored they are and to text them at ***-***-****, it’s not a good move.

Update: A Facebook rep tells Consumerist:

“This update does not change anything about how ads are shown on Facebook, either to teens or others. Currently, sponsored stories are only shown to friends, regardless of the audience of your post.”

That’s good to know, but by the very act of posting publicly, teens are still opening themselves up to data brokers, which can then pass that information on to clients and marketers, the better to target Facebook users with ads.

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