If you are a Twitter addict, you may have noticed that Twitter was down today (Thursday) morning. The reason for downtime was a DoS (Denial of Service) attack.

A DoS attack consists of sending more amount of traffic to a website or server than it can handle. Usually, such attacks are executed from multiple computers via malware.

Twitter’s co-founder Biz Stone wrote in a blog post, “Attacks such as this are malicious efforts orchestrated to disrupt and make unavailable services such as online banks, credit card payment gateways, and in this case, Twitter for intended customers or users,” he said. “We are defen

ding against this attack now and will continue to update our status blog as we continue to defend and later investigate.”

Twitter was unavailable to users from 9:15 am EDT on Thursday for around two and half hours. Twitter’s last downtime was on May 30, 2009 which was caused by a software error.