It was reported that Yahoo was receiving data at the rate of 1 gigabyte per second at the peak of the ddos attack on it in February 2000. In future years this will sound trivial but currently this is an astounding amount of data. It really raises the question of whether the problem was just faulty network hardware.

A DDoS attack consists of pinging a broadcast server with a forged IP signature. The broadcast server then sends that packet to its minions (other servers with the DDoS software installed), and they in turn ping the IP that was forged. This floods the computer being attacked with ping requests, which brings down the network it's on, and/or uses up system resources, and/or knocks the computer off of the internet.

See: buffer overflow attack, SYN attack, teardrop attack, smurf attack, physical infrastructure attack