WASHINGTON -- As the Pentagon warns of the security risks posed by social networking sites, newly released government documents show the military also uses these Internet tools to monitor and react to coverage of high-profile events. 

The Air Force tracked online messaging service Twitter, video-sharing site YouTube and various blogs to assess the huge public backlash to the Air Force One flyover of the Statue of Liberty this spring, according to the documents. 

And while the attempts at damage control failed -- "No positive spin is possible," one PowerPoint chart reads -- the episode opens a window into the tactics for operating in a boundless digital news cycle. 

This new terrain has slippery slopes, though, for the military.  Facebook, MySpace and other social media sites are very popular among service members, including those in

Iraq and Afghanistan who want to keep in touch with friends and family.  The sites are also valued by military organizations for recruiting or communicating with other federal agencies. 

But posting information on these interactive links makes it vulnerable to being lost or stolen by the enemy, according to Pentagon officials.  On Thursday, a hacking attack shut down Twitter for several hours, while Facebook had intermittent access problems -- an indication of the shortcomings of relying on these services. 

The Marine Corps' computer network blocks users from accessing social media sites, which service officials say expose "information to adversaries" and provide "an easy conduit for information leakage." 

The Marines recently made its ban official.  And that prohibition might extend to other parts of the military pending a top-level review ordered in late July by Deputy Defense Secretary Bill Lynn. 

In a widely distributed memo, Lynn said the so-called "Web 2.0" sites are important tools but more study is needed to understand their threats and benefits. 

Air Force officials are already aware of the potential benefits. 

According to the Air Force One documents released through the Freedom of Information Act, a unit called the Combat Information Cell at Tyndall Air Force Base in Florida monitored the public fallout from the April 27 flight and offered recommendations for dealing with the fast-breaking story. 

Formed two years ago, the cell is made up of as many as nine people who analyze piles of data culled from the Internet and other sources to determine whether the Air Force's message is being heard. 

The presidential plane took off for New York from Andrews Air Force in Maryland accompanied by two F-16 jet fighters.  The purpose of the flight, which was not publicly announced, was to get new photos of the specially modified Boeing 747 with the statue in the background. 

The mission quickly became a public relations disaster as panicked New Yorkers, fearing another 9/11-style attack, emptied office buildings.  In the aftermath, Louis Caldera, director of the White House military office that authorized the flight, was fired. 

The Combat Information Cell's first assessment of the event said "Web site blog comments 'furious' at best."  Local reporting of the flyover was "very critical, highlighting scare factor," it added. 

A search of Twitter, which allows people to post messages of 140 characters or less to a circle of friends, family or fans, showed that users were posting a rate of one message, or "tweet," per minute about a pair of F-16s chasing a commercial airliner, the cell said. 

Media coverage over the next 24 hours "will focus on local hysteria and lack of public notification," the cell predicted. " Blogs will continue to be overwhelmingly negative." 

"Damage control requires timely counter-information," but the opportunity for that had passed, the assessment said.  The cell recommended acknowledging the mistake and ensuring it didn't happen again. 

Another update on April 28 said the story was still "reverberating, surprisingly resilient."  The tweet rate had grown to three per minute and the words "New York" had been pushed into Twitter's list of most talked about topics.  Videos of the event posted on YouTube had been viewed more than 260,000 times, it said. 

By April 30, the story had faded, the cell reported.  The blogs were still very critical, but it was the White House, not the Air Force, that was taking the heat, the assessment for that day said. 

The other dominant news story at the time was public concern over the spread of swine flu.  According to the documents, the same Air Force cell suggested there may be an opportunity to turn the tide. " Government involvement in this incident could be used to frame expected handling of H1N1 outbreak," one of the PowerPoint charts reads. 

A Utah Air National Guard unit, the 101st Information Warfare Flight in Salt Lake City, was also monitoring the social sites. " To say that this event is being beaten like a dead horse is an understatement," reads an April 28 e-mail from the unit to other Air Force offices. " Has really taken off in Web 2.0." 

Both the 101st and the Combat Information Cell are attached to the 1st Air Force, which is based at Tyndall and is in charge of guarding U.S. airspace. 

1st Air Force spokesman Al Eakle explained that the command had no role in planning or coordinating the Air Force One flight.  But the units tracked social networks and blog traffic "to obtain what lessons we might learn so as not to repeat them in the future."  The assessments were sent to the command's leadership so they'd know how the public was reacting, he added.