Facebook also unilaterally and repeatedly changed the privacy settings on user data between 2009 and 2010. At the time, CNIL and the other European Union data protection authorities that together form the Article 29 Working Group strongly criticized these changes, some made without users' knowledge. If users weren't vigilant, or if they accepted Facebook's default settings, then messages that had previously been private or accessible only by friends suddenly became available to anyone. And since the affected messages could be quite old, it was not always obvious to users that their potential audience had changed.
The recent introduction of the Timeline, a new way of visualizing messages and other activities on Facebook all the way back to the creation of the account, suddenly made these messages more visible, CNIL said.
While CNIL found that the recent discovery of these old messages was the fault of Facebook, but of its users, it nevertheless reiterated the calls it and other data protection authorities have made in recent years for social networks to take steps to protect users' privacy.
Those steps include being more transparent about their use of personal data; providing better tools for users to control the publication of their personal data; requiring users to opt in before activating new functions or passing their personal information to third parties, and making default privacy settings more protective of personal data, especially when unilateral changes are made to privacy policies or settings.
Peter Sayer covers open source software, European intellectual property legislation and general technology breaking news for IDG News Service. Send comments and news tips to Peter at firstname.lastname@example.org.