Twitter forced offline after cyber attack

Popular social network Twitter crashed on Thursday afternoon after falling victim to a malicious online attack.

Frustrated tweeters began posting on online forums at around 3pm GMT as they searched for the reason behind the downtime.

An hour later, a blog post by Twitter co-founder Biz Stone revealed the site had been targeted by a denial of service attack, the term used to describe a period in which servers are deliberately flooded with more requests than they can cope with.

"On this otherwise happy Thursday morning, Twitter is the target of a denial of service attack," he said. "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."

Speculation about the individuals behind the incident have spread quickly across the internet.

Writing in his blog, Graham Culley, senior technology consultant at Sophos, said: "The question on my mind is - why would someone want to attack Twitter? I can't imagine it's a commercial competitor of theirs, but it could be someone with a political or financial motivation (blackmail?), or a teenager in a back bedroom with access to an awfully large botnet."

Culley also claimed that the impact of the downtime won't just be felt by celebrities posting "meaningless piffle".

"Companies are using it to keep in touch with their customer base, and consumers take advantage of the site's intimacy to get an answer from large companies that are discovering how to have a "human face" online," he said.