Facebook has been suffering from intermittent outages since Thursday night and a hacker group is taking responsibility.
Users around the world began complaining on Twitter last night that they were unable to access the social network. The complaints continued early Friday morning.
And Anonymous, a well-known hacker collective, is taking credit for the off-and-on service failures.
"Looks like good old FaceBook is having packet problems...," a Twitter account called YourAnonNews tweeted Thursday night. "Oh yeah... RIP Facebook a new sound of tango down bitches," the account tweeted an hour later.
And GarmiMobar tweeted to Anonymous: "Oh... I was wondering why I couldn't enter my fb account! :) Keep up the good work, Anons!"
However, a Facebook spokesman told Computerworld today that the downtime was not caused by an attack. The company did not specify what was causing the trouble.
"Yesterday some users briefly experienced issues loading the site," wrote Michael Kirkland, a Facebook spokesman. "The issues have since been resolved and everyone should now have access to Facebook. We apologize for any inconvenience."
According to Apica, a load testing and performance monitoring company, Facebook suffered intermittent outages both Thursday night and Friday morning.
Apica reported that Facebook had high response times and sporadic unavailability between the hours of 8:28 p.m. and 10:29 p.m. ET last night, and between 3 a.m. and 6 a.m. today.
The site was unavailable at 8:28 p.m., 8:33 p.m., 10:19 p.m., and 10:29 p.m., and again at 9:47 a.m. And users were quick to vent their frustrations, as well as have some fun at Facebook's expense, on Twitter.
"Facebook is currently down. The world's productivity just increased by 1200%," tweeted JohnMikulski.
Another Twitter user, OptimusSubprime, tweeted: "Yes, folks, it's true, #facebook is down. You'll have to go somewhere else to find out who went to Red Lobster after work today."
It's bad timing for Facebook to suffer wide-spread outages.
The social network has been taking it on the chin since its initial public offering last month. The company's stock, which was initially offered at $38 per share, has steadily sunk in price. On Friday at 12:45 ET, the stock price was at $28.08 per share.
"Facebook is acting like its stock. It keeps going down," tweeted HAL9000_.
Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, on Google+ or subscribe to Sharon's RSS feed . Her email address is email@example.com.