What Japan lacks in geographic size, it more than makes up for in Internet attack traffic.

Japan accounted for 30 percent of all attack traffic monitored worldwide for the second quarter of 2008, according to a new study issued by content delivery network provider Akamai. The study, which was conducted by monitoring Akamai's global network of more than 30,000 servers, measured distributed denial-of-service attacks, Web site hacking attempts and DNS hijackings for 139 countries around the world. The United States had the second-highest percentage of attack traffic for the second quarter, at 21.5 percent, while China came in third at 16.8 percent.

Japan's high percentage of global attack traffic marks a big jump from the country's percentage of attack traffic in the first quarter, which accounted for only 3.6 percent of traffic worldwide. Akamai says it is unsure why so much attack traffic originated from Japan this quarter, and noted that "there does not appear to be a clear and obvious link between the high-speed connectivity and the likelihood that a country is a leading source of attack traffic." Japan ranks third in high-broadband IP connections per capita, Akamai reports, trailing only South Korea and Sweden.

In addition to reporting on global attack traffic, the study also found that:

• Scandinavian countries continue to lead the world in unique IP addresses per capita, with Sweden, Norway and Finland accounting for three of the top four countries in IP connectivity worldwide. The United States, with 0.34 unique IPs per capita, placed seventh in the world.

• 26 percent of US Internet connections achieve speeds of 5Mbps or greater, placing the United States sixth in the world for the highest percentage of high-speed Web connections. The top country is South Korea, where 64 percent of all connections are at speeds of 5Mbps or higher, followed by Japan with 52 percent and Hong Kong with 39 percent. The United States also ranked fifth in per-capita high broadband connections, with 0.09 connections of 5Mbps or greater per capita.

• The United States currently ranks 15th worldwide in broadband density, with an average of 23.3 broadband subscribers per 100 residents. Denmark ranks first in the world with 35.1 broadband subscribers per 100 residents.