It's a tactic used to knock websites offline, both big and small. But whole countries? You betcha.

DDoS attack boots Kyrgyzstan from net - The Register

The central Asian republic of Kyrgyzstan was effectively knocked offline for more than a week by a Russian cybermilitia that continues to flood the country's internet providers with crippling data attacks, a security expert said.

The attacks, which began on January 18, bear the signature of pro-Russian nationalists believed to have launched similar cyber assaults on the republic of Georgia in August, said Don Jackson, a researcher with Atlanta-based security provider SecureWorks. The attacks on Kyrgyzstan were so potent that most net traffic in and out of the country was completely blocked during the first seven days.