Facebook has denied claims that a bug on the site is publishing users' private messages, saying they were originally posted by users voluntarily.
But the company's insistence it has done nothing wrong could not spare its share price, which fell more than 9 nine per cent amid the rumours at the close of trading yesterday.
Reports began to surface yesterday of some claiming that private messages they sent to other people on the site between 2007 and 2009 were reappearing as posts visible to all of their friends. The allegations were first reported in the French newspaper Metro France and were quickly seized upon by technology blogs and newspapers.
Facebook confirmed last night that the rumours were false but users' fears appear to have already spread to investors as the company's stock slumped 9.06 per cent on the New York stock exchange, its worst fall since June.
After readers of technology websites began writing in, claiming they were seeing a similar problem, concerns were raised of a highly damaging privacy breach at Facebook.
The leading blog The Next Web reported a host of readers' complaints from across the world that the problem was affecting them. Readers said it was happening in the UK, in the Philippines and in Canada. One of the blog's reporters in France also said she was experiencing the problem.
A later update to the story claimed: “Reports are coming in from readers all over the world saying private messages have appeared on their Timeline,” although the blog warned readers to be wary of the difference between messages posted publicly and those posted privately in the past.
After an internal investigation into the claims, Facebook confirmed that old messages were reappearing but said that they were in fact posts the users themselves had originally published to their friends, rather than private messages.
A spokesman said: “A small number of users raised concerns after what they mistakenly believed to be private messages appeared on their Timeline. Our engineers investigated these reports and found that the messages were older wall posts that had always been visible on the users' profile pages. Facebook is satisfied that there has been no breach of user privacy.”
And the spokesman told TechCrunch: “Every report we've seen, we've gone back and checked. We haven't seen one report that's been confirmed. A lot of the confusion is because before 2008 there were no likes and no comments on wall posts. People went back and forth with wall posts instead of having a conversation.”Reuse content