On Monday, the Facebook revealed that a bug had affected 800.000 user privacy settings. This bug allows users who have been blocked from Facebook and Messenger to have access to it again - without those who have been blocked to know it.
According to statement that made Facebook about the subject, in 83% of people affected by this error only one person broke temporarily than the ones that were totally blocked. At the other 17 percent of users, however, there were more than one person who unblocked because of the error.
Users who were unblocked could not see content shared with those friends who blocked them. However, it is likely that they were able to communicate with the one who had blocked them via Messenger and see public posts that were not just tagged for friends.
While the problem is resolved now, the bug was active for 8 days, affecting users from 29 May to June 5.
Facebook further clarified what happened on Twitter. According to the company, visible Facebook user data is stored in pairs called "associations". The error deleted some links to Facebook and Messenger, which caused the loss of privacy settings for affected users.
In his original statement, Facebook highlighted the reasons why someone might want to block another user. From trying to "take a break from someone who publishes content that finds annoying" to even more serious reasons, such as harassment and intimidation, blocking is very important to make Facebook a safe place for its users.
In his statement, it is clear that Facebook understands the possible consequences of this error. However, following recent events, it appears that the company needs to do much more in terms of the privacy of its users.