Washington (CNN) -- U.S. military personnel are officially allowed to tweet.
That's the upshot of the Pentagon's long-awaited policy on rank and file personnel using online social media, unveiled Friday. The new rules authorize access to Facebook, Twitter, YouTube, and other social media Web sites from nonclassified government computers -- as long as such activity doesn't compromise operational security or involve prohibited activities or Web sites.
Until now, the military's various branches and departments had differing policies regarding social media use. The Marine Corps, for instance, prohibited use of social media sites from its computers in 2007, according to the Pentagon.
The Pentagon announced the policy Friday via social media such as Facebook and Twitter, in addition to using the Department of Defense's Web site, said spokesman Bryan Whitman.
"This directive recognizes the importance of balancing appropriate security measures while maximizing the capabilities afforded by 21st century Internet tools," said Deputy Defense Secretary William J. Lynn III, who signed the policy.
The new policy denies military personnel access to sites promoting gambling, pornography or hate crimes from government computers.
"The world of Web 2.0 and the Internet provides these amazing opportunities to collaborate," said David M. Wennergren, deputy assistant secretary of defense for information management and technology. "It not only promotes information sharing across organizational boundaries and with mission partners, but also enables deployed troops to maintain contact with their loved ones at home."
The new policy allows commanders to temporarily restrict online access to maintain operations security or to address bandwidth constraints.