United States troops are to be allowed to use social networking websites such as Twitter and Facebook following a review of internet use and security.
Defence Department officials say the benefits of using social media now outweigh the risks to security.
Sites blocked by the Pentagon in 2007 - including YouTube - will now be unblocked, although commanders will be able to temporarily block access in order to safeguard missions or save bandwidth.
The BBC reports that social media and the internet are becoming increasingly important for the US military. The web is used for recruitment, public relations and for communications between troops and their families, among other things.