A bug redirected people from third-party websites integrated with Facebook to Facebook.com. for a short period of time, the social networking website said.
The temporary glitch, which affected users on Thursday afternoon, appeared to affect those who were logged into Facebook when they visited the third-party sites in question. Users reported being redirected to Facebook's site and an error message that said, "An error occurred. Please try again later."
Thousands of sites that use some form of Facebook integration were being redirected to an error page on Facebook, driving all traffic away from their original site destination, wrote blogger Abe Olandres in the Philippines. He said his blog had also been affected.
Users took to Twitter to complain about the redirection. "Is it just me or does every website that has a Facebook like button redirect me to Facebook," wrote Fresh Aesthetics.
The short-duration glitch, however, raised questions about the consequences of tighter integration by websites with Facebook and other services.
"I suspect many don't quite grasp the implications of running 3rd party code (i.e Facebook Connect, Google Analytics, etc) on their website," said independent researcher Ashkan Soltani in a Twitter message.
Facebook Connect is a set of application programming interfaces (APIs) from Facebook that allow members to log onto third-party websites and apps using Facebook accounts, and share information with their friends on the social network.
The incident is a reminder that as a lot of website owners and web masters are slowly integrating some of their critical services with Facebook, the social network could become a single source of problems when similar incidents happen in the future, Olandres wrote.
"So, given that Facebook effectively has the power to redirect anyone using their plugins isn't it time we have a serious talk about Facebook," said user Woodo on Twitter. "So are all these sites going to sue Facebook for their lost ad revenue tonight?" asked another user.
"The issue was quickly resolved," the company said in an emailed statement. It did not, however, provide information on what caused the bug. "We currently have nothing else to share," a Facebook spokespersonn said.