The Wall Street Journal continues its excellent privacy series and unleashes another PR headache for Facebook, which is allowing third-party software companies to access and distribute users’ identities.

Facebook is scrambling to contain the damage, but it’s worth noting up high that the Journal wrote a similar story in May on this issue.

Back then it reported that Facebook was sending user IDs to advertisers. Facebook supposedly discontinued the practice after that report. This time it’s app developers that are getting the IDs. And now Facebook is again scrambling to discontinue the practice after a WSJ report.

You’re telling me some Wall Street Journal reporters know about this problem but Facebook itself didn’t? I don’t believe that. So why is Facebook only doing something about it after the problem is exposed? That’s all the more reason to continue the intense press scrutiny of this company.

The Journal’s got the goods here in this excellent investigation. Here’s more reason to believe Facebook had to know about this problem:

The Journal found that all of the 10 most popular apps on Facebook were transmitting users’ IDs to outside companies…

Three of the top 10 apps, including FarmVille, also have been transmitting personal information about a user’s friends to outside companies.

And this is critical here: The paper found that at least one of these outside companies is snatching up this information and putting it to use:

The apps reviewed by the Journal were sending Facebook ID numbers to at least 25 advertising and data firms, several of which build profiles of Internet users by tracking their online activities.

Defenders of online tracking argue that this kind of surveillance is benign because it is conducted anonymously. In this case, however, the Journal found that one data-gathering firm, RapLeaf Inc., had linked Facebook user ID information obtained from apps to its own database of Internet users, which it sells. RapLeaf also transmitted the Facebook IDs it obtained to a dozen other firms, the Journal found.

Great work by the Journal.

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Ryan Chittum is a former Wall Street Journal reporter, and deputy editor of The Audit, CJR's business section. If you see notable business journalism, give him a heads-up at rc2538@columbia.edu. Follow him on Twitter at @ryanchittum.