Screenshot by Chris Matyszczyk/CNET

It has now been firmly established -- by Randi Zuckerberg, no less -- that Facebook is the home of human decency.

How is it possible, then, that 18-year-old Jacob Cox-Brown of Astoria, Ore., did not receive the message?

For, according to KGW.com, Cox-Brown had the indecent temerity to post this to his Facebook page: "Drivin drunk... classsic ;) but to whoever's vehicle i hit i am sorry. :P."

This was, indeed, a classsic (sic) example of misbegotten sharing.

For police -- who had concluded that not one but two vehicles had been struck by an unknown driver -- now concluded that the driver was Jacob Cox-Brown.

How did they manage this? By the saddest reality of all. Two of Cox-Brown's alleged friends reportedly contacted the law in order, one imagines, to restore human decency.

The police issued a press release that read: "Astoria Police have an active social media presence. It was a private Facebook message to one of our officers that got this case moving, though. When you post...on Facebook, you have to figure that it is not going to stay private long."

No, not long at all, as Randi Zuckerberg can attest.

Cox-Brown has been charged with two counts of failing to perform the duties of a driver. These, presumably, include not hitting other vehicles.

While Randi Zuckerberg railed that you can't trust the friends of friends, Cox-Brown now seems to have realized that you can't even trust your friends.

At least those who claim to be your friends on Facebook.