According to a memo sent by Gen. B.B. Bell, the U.S. Forces Korea commander, the Defense Department will block access from its networks and computers to some social-networking and video sharing sites.

The official reason is the heavy traffic generated by overseas US soldier and the risks posed to information security. "This recreational traffic impacts our official DoD network and bandwidth ability, while posing a significant operational security challenge," the memo concludes.

The list covers 11 sites like the video-sharing sites YouTube, Metacafe, IFilm, StupidVideos, and FileCabi, the social networking sites MySpace, BlackPlanet and Hi5, and the photo-sharing site Photobucket. Also included in the list are sites like Pandora, MTV, and 1.fm, and live365.

“We’re not passing any judgment on these sites, we’re just saying you shouldn’t be accessing them at work,” said Julie Ziegenhorn, spokeswoman for U.S. Strategic Command. “This is a bandwidth and network management issue. We’ve got to have the networks open to do our mission. They have to be reliable, timely and secure.”

According to Ziegenhorn a review of the banned sites has been under way since February “This will be an ever-evolving discussion, because we need to constantly make sure those networks are available and secure,” she said.