Twitter, Facebook, LiveJournal, Google Blogger and other Web sites were hobbled Thursday -- Twitter was completely down for many users -- and it all appears to have been because of a coordinated online attack on one political blogger in the Republic of Georgia.
The man called himself "Cyxymu." ABC News tracked him down in Tblisi, Georgia, and spoke to him by phone.
He said he is a 34-year-old economics professor named Georgy (he wouldn't give his last name), a married father of two. He said he is a refugee from Abkhazia, a region of Georgia that declared its independence in 1991 after the breakup of the Soviet Union, but is recognized by only a few of the world's governments.
Georgy said he started a blog on the LiveJournal site to unite fellow refugees who would like Abkhazia to recognize Georgia's authority over it. Last summer, Georgia and Russia went to war with each other, and Georgy started criticizing Russia -- which recognized his homeland's independence -- online.
Georgy said he believes he was targeted by a group linked to the Kremlin. "It's hard to say who did it but I looked at how it was done and it definitely cost a lot of money. An operation like this couldn't have been done by a group of enthusiasts."
What they did is known as a Denial of Service attack (DoS). They sent out computer viruses that infected thousands of computers around the world -- and, at a specified time, inundated the sites used by Georgy with e-mails.
Twitter, its servers apparently overwhelmed, was unavailable to many users for more than a day; Facebook and LiveJournal confirmed they had disruptions.
"I tried LiveJournal, it didn't work," said Georgy. "I tried Facebook and it didn't work. Then I tried Twitter and it didn't work. I then realized that something serious had happened. I didn't connect it to myself at first, I didn't imagine that I could have caused it."
Twitter, based in California, could not immediately be reached for comment. Facebook replied to queries from ABC News with a statement:
"Yesterday's attack appears to be directed at an individual who has a presence on a number of sites, rather than the sites themselves. Specifically, the person is an activist blogger and a botnet was directed to request his pages at such a rate that it impacted service for other users. We've isolated the issue and almost all of our users are able to enjoy the normal Facebook experience."
Twitter, Facebook Hobbled by Attack on a Single Georgian Blogger
Meanwhile, back in Tblisi, Georgy said he only realized the outage was connected to him when he gained access to his accounts again and found tens of thousands of e-mails. Hundreds of thousands of e-mails went out in his name, he says.
Georgy said he doesn't use Twitter very much, but he was impressed by its capacity for quickly disseminating information. He said he saw the way it was used by dissidents this spring in Iran, and says he has apologized to several Iranian bloggers for the disruption.
He said he doesn't believe that it's his fault, but he is sorry it happened and says once back online, he apologized to those who follow his online postings.
His views have not changed. "Cyxymu" is an alternative name for Sukhumi, the capital of Abkhazia.