Content distribution networks (CDN) like Akamai are used by many sites that experience extremely heavy web traffic. Some organizations, including the campaign site of Bush’s opponent, Sen. John Kerry, use Akamai specifically to manage file downloads. Akamai’s network includes more than 15,000 servers in data centers throughout the world, which store and distribute web site content, easing bottlenecks that can occur when serving a large volume of requests from a single server.

Akamai’s EdgeScape service allows web sites to customize content – or exclude visitors – according to geography. Criteria for geography-based content are set by the customer, and implemented by Akamai’s network.

Excluding non-U.S. requests could be denying access to the Bush campaign site to some registered voters, including American residents who are living overseas but eligible to vote by absentee ballot. Overseas ballots became an issue in the 2000 election, when backers of Bush and Democratic candidate Al Gore fought for every vote amid legal wrangling over recounts in Florida.

At least 340,000 U.S. military personnel stationed outside the U.S. have requested absentee ballots, according to the Pentagon. Most U.S. soldiers and seamen with Internet access would presumably access the Internet through the .mil domain reserved for the U.S. military, which would allow those requests to be handled differently than other non-US traffic.

Last week’s simultaneous outages for GeorgeWBush.com and RNC.org prompted speculation that an electronic attack may have ocurred, as the two sites are hosted on separate web servers. The Bush campaign told media the outage was “no big deal” and offered no specific explanation for the outage.

CDNs can be effective in blunting the impact of distributed denial of service (DDoS) attacks, which seek to overwhelm web sites with traffic, leaving them unavailable. Microsoft used a CDN service from Akamai to keep its web site online in August 2003, when the Blaster worm programmed machines to launch a DDoS on the Windows Update site.

Akamai itself came under a DDoS attack in August, when an attack by a large “botnet” of compromised computers controlled by hackers.

Akamai declined comment on the traffic management of GeorgeWBush.com.