Those included posting private data, including credit-card and Social Security numbers, of Web users and launching distributed denial-of-service (DDoS) attacks against media sites who posted stories they didn't like.

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Security experts say the attack uses more sophisticated techniques than most DDOS (distributed denial of service) attacks and targets the Web's infrastructure, which has led to other sites performing slowly.

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Within hours, according to the cybersecurity researchers at Panda Labs, the loose group of hackers that calls itself Anonymous launched a distributed denial of service attack that threw junk traffic at the web server of the blog that had made the WikiLeaks announcement, and by 4am had taken the site offline.

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Security experts said the attack used more sophisticated techniques than most distributed denial of service, or DDoS, attacks and targeted the Web's infrastructure, which led to other sites performing slowly.

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Both were accused of carrying out distributed denial of service (DDoS) attacks, which refer to flooding web applications with so many online requests that they temporarily shut down.

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Spamhaus accused Cyberbunker, a Dutch Web-hosting company, of coordinating the so-called distributed denial-of-service attack against it, according to a report by the British Broadcasting Corp.

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Botnets can send spam and flood Web sites with countless requests for information, a cyber attack also known as distributed denial of service.

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Russian hackers, meanwhile, took to the Net, launching waves of distributed denial-of-service attacks against the country's government, banking and media Web sites, using thousands of personal computers hijacked with hidden software to overload the servers.

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