The distributed denial-of-service (DDOS) attacks that knocked out Twitter for hours and affected other sites such as Facebook, Google's Blogger and LiveJournal on Thursday continued all day Friday and persisted over the weekend (see 'Twitter down: killed by DOS attack').
In an update, posted to a discussion forum of its third-party developers early on Saturday, Twitter said it was still fighting the attacks.
"The DDoS attack is still ongoing, and the intensity has not decreased at all," wrote Chad Etzel early Saturday, from Twitter's application development platform support team.
This means that Twitter will maintain a set of defensive measures that have allowed it to keep the site up but that also have affected the interaction of third-party applications with the site via its API (application programming interface). "At this point, removing any of those defenses is not an option," Etzel wrote.
Early this morning, while Twitter.com was working, many third-party apps were unable to access the service. Most seem to be working correctly as of 9am GMT.
"Things will continue to be rocky as long as this attack continues. They may get worse, they may get better. That should not be read as 'we don't care about fixing it' or 'we're not going to fix it until everything blows over' but instead as 'we can't promise when things will be back to normal, but in the meantime we are working on fixing ASAP,'" Etzel wrote.
As was the case on Thursday, Twitter wasn't the sole target of the DDOS attacks on Friday and over the weekend. Google's Blogger blog publishing service felt the sting of the attacks on Friday afternoon as well.
"A small percentage of Blogger users have experienced error messages this afternoon as the result of what appears to be an ongoing distributed denial of service attack aimed at multiple services across the web," a Google spokesman said via email.
"Google has a variety of systems in place to help counteract these types of attacks, and we believe the majority of affected users can now access their blogs. We're continuing to work to minimize the impact to affected Blogger users. No other Google products have been affected," the spokesman said on Friday afternoon.
Facebook, whose site experienced some performance problems on Thursday due to the attacks, acknowledged on Friday afternoon that the attacks had continued. "The requests from the botnet continue but we have been able to isolate them and provide normal levels of service to our legitimate users," a Facebook spokesman said via email on Friday afternoon.
According to news reports and information from companies affected, the attacks appear directed at silencing a blogger in the country of Georgia who has been critical of Russia's actions and policies toward that neighbouring country (see 'Twitter DOS attack targeted Georgian blogger').