Edward Lucas has an article on the cyber attack on Estonia - quite scary stuff really. They've basically forced the Estonians to cut off access to their websites from overseas. Some of this is from angry Russians, but a lot is from botnets, the collections of easily-hacked computers from across the world run by shadowy figures.
This is like the cold war again, except in cyberspace - sending guerrilas to disrupt your enemy without actually sparking a war.
Hat-tip - Cicero's Songs