A massive distributed denial of service attack that simultaneously blasted a single user's Twitter, Facebook and Livejournal accounts was blamed for bringing the social media world to a grinding halt.
The blogger, cyxymu, shared their name with a town in the Republic of Georgia.
Facebook chief security officer Max Kelly said the user had accounts with all three affected websites.
"It was a simultaneous attack across a number of properties targeting him to keep his voice from being heard," Kelly told CNET News.com.
Symantec Managed Services senior manager Peter Sparkes said the downtime was unlikely to worry big organisations because social networking sites were far from "mission-critical".
"Businesses use instant messenger, Twitter and Facebook for recruiting and all sorts of other functions," Sparkes said.
"At the moment, I suspect they are not mission-critical and not too many firms are concerned about this instance."
But he said organisations were likely to become more reliant on social media services in the future.