Facebook has said that it too was subject to a DDoS attack on Thursday.

"You may have had trouble accessing Facebook earlier today because of network issues related to an apparent distributed denial-of-service attack," said the social networking site on its own Facebook profile. "We have restored full access for most people. We’ll keep monitoring the situation to make sure you have the reliable experience you expect from us".

The news comes following a similar attack against Twitter that was successful in taking the micro-blogging site off line for several hours on Thursday.

"A denial of service attack occurs when computers bombard a website with requests for information," explains Antivirus company Sophos.

"Typically hackers can control thousands of innocent users' computers centrally and command them to visit a site that they wish to flood with traffic - making it impossible for other internet users to get through. It's a bit like 15 fat men trying to get through a revolving door at the same time - nothing can move".

Google is reported helping the two companies investigate into the source of the attacks. At this point in time, it is not sure whether they are related.

Microsoft's LiveJournal site was also reportedly affected by a DDoS attack on Thursday, while Gawker, publisher of a number of blogs including Gizmodo was also taken down by a DDos earlier in the week.

Is it a plot or some whacked out conspiracy theory? Let us know what you think in the comments below.

All the affected sites appear to be up and running again.