Twitter was attacked by hackers and was down for over an hour today.

With an estimated 2.4 million users, the Twitter social networking website was offline for around an hour on Thursday 6 August, after it became the victim of an attack.

 Users were unable to “tweet” this afternoon in the UK, when a message on the Twitter company blog stated that the short messaging site was the target of a “denial of service attack”.

At 1.00pm GMT, it 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.”

“We are defending against this attack now and will continue to update our status blog as we continue to defend and later investigate.”

A message then appeared on the site’s status blog later in the afternoon saying the site was back up. The update said: “We are continuing to defend against and recover from this attack.”

Denial-of-service attacks or DDOS attacks (for distributed DOS) – happen when the controllers of “botnets” consisting of many thousands of virus-compromised Windows PCs decide to target a site. In the past banking, gambling and news sites – and even Google – have been the target of DDOS attacks.

The attacks use the electronic equivalent of ringing the site’s doorbell and running away: the targeted sites server wastes its resources answering the call. In a typical DDOS attack, there may be millions of such fake approaches.

Twitter seems to be perfectly fine at the time of writing, and the attack is now of course one of the top trending topics!