Over the course of 10 months in eastern Afghanistan, an Army specialist nicknamed Mud Puppy maintained a blog irreverently chronicling life at the front, from the terror of roadside bombs to the tyrannies of master sergeants.

Often funny and always profane, the blog, Embrace the Suck (military slang for making the best of a bad situation), flies under the Army's radar. Not officially approved, it is hidden behind a password-protected wall because the reservist does not want his superiors censoring it.

“;Some officer would be reviewing all my writing,”; the 31-year-old soldier, who asked that his name not be used, said in an e-mail message. “;And sooner or later he would find something to nail me with.”;

There are two sides to the military's foray into the freewheeling world of the interactive Web. At the highest echelons of the Pentagon, civilian officials and four-star generals are newly hailing the power of social networking to humanize troops, entice recruits and shape public opinion on the war.

Gen. Ray Odierno, commander of American forces in Iraq, is on Facebook. The chairman of the Joint Chiefs of Staff, Adm. Mike Mullen, has a YouTube channel and posts Twitter updates almost daily. The Army is encouraging personnel of all ranks to go online and collaboratively rewrite seven of its field manuals. And on Aug. 17, the Department of Defense unveiled a Web site promoting links to its blogs, Flickr, Facebook, Twitter and YouTube sites.

The Web, however, is a big place. And the many thousands of troops who use blogs, Facebook, Twitter and other social media sites to communicate with the outside world are not always in tune with the Pentagon's official voice. Policing their daily flood of posts, videos and photographs is virtually impossible—but that has not stopped some in the military from trying.

The Department of Defense, citing growing concerns about cybersecurity, plans to issue a new policy in the coming weeks that is widely expected to set departmentwide restrictions on access to social networking sites from military computers. People involved with the department's review say the new policy may limit access to social media sites to those who can demonstrate a clear work need, like public information officers or family counselors.

If that is the case, many officials say it would significantly set back efforts to expand and modernize the military's use of the Web, just as those efforts were gaining momentum. And while the new policy would not apply to troops who use private Internet providers, a large number of military personnel on bases and ships across the world depend on their work computers to gain access to the Internet.

To many analysts and officers, the debate reflects a broader clash of cultures: between the anarchic, unfiltered, bottom-up nature of the Web and the hierarchical, tightly controlled, top-down tradition of the military.

“;We as an institution still haven't come to grips with how we want to use blogging”; and other social media, said Lt. Gen. William B. Caldwell IV, the commander of the Army Combined Arms Center at Fort Leavenworth, Kan.

One of the Army's leading advocates for more open access to the Web, Caldwell argues that social networking allows interaction among enlisted soldiers, junior officers and generals in a way that was unthinkable a decade ago. He requires students at the Command and General Staff College at Fort Leavenworth to blog, and the college now sponsors 40 publicly available blogs, including his own, where policies are freely debated.

But getting approval for those blogs, as well as for YouTube and Facebook access at the college, was a struggle. “;At every corner, someone cited a regulation,”; Caldwell said. In recent months, however, “;the Army has made quantum leaps”; in embracing the Web, he added.

Noah Shachtman, editor of Wired.com's national security blog, Danger Room, which has reported extensively on the new policy review, said he recently asked students at West Point whether they would allow soldiers to blog. Almost every cadet said no.

“;Then I asked, 'How many of you think you can stop the flow of information from your soldiers?' “; Shachtman recalled. “;Everybody agreed there is no way to stop this information from going out anyway. So there is this sort of dual-headedness.”;

Skeptics of the Pentagon review say it is motivated partly by a desire among certain officials to exert control over the voices of troops on the Web. Since the advent of military blogging during the Iraq war, some commanders have remained uncomfortable with the art form, citing concerns about both security and decorum.

Over the years, blogs have been censored or shut down, and several years ago the Army instituted requirements that bloggers register with their commanding officers and submit posts for review. As a result, some bloggers say, blogs have become tamer—or, as in the case of Mud Puppy's blog, gone underground.

Officials knowledgeable about the review say it is the result of growing concerns at the U.S. Strategic Command, which oversees the military's use of the Internet, that social networking sites make military computers vulnerable to viruses, hackers, identity thieves, terrorists and even hostile governments. (Those concerns are not focused on the military's secure system for classified material, which does not use the public Internet.)

The review may already be having a chilling effect. The Marine Corps recently restated a ban on using any social media on its network. And the Army, which in June gave some bases access to Facebook, Twitter and other networking sites, recently urged units to avoid creating new social media pages until the final department policy was issued.

Still, even as they consider restricting the troops' access to social media, the most senior Pentagon officials have clearly come to view Facebook, Twitter, YouTube and blogging as crucial elements of their public information operations.

“;This department, I think, is way behind our curve”; in using social media, Secretary of Defense Robert M. Gates said in July as he extolled the use of Twitter by Iranian dissidents.

To critics, the Pentagon's social media sites are goofy at best, propagandistic at worst. “;It's like your parents' using modern slang and failing miserably,”; said Sgt. Selena Coppa, who writes a blog, Active Duty Patriot, which frequently criticizes the Iraq war and, she says, has gotten her into trouble with her superiors.

But to many troops, the deeper question is whether the military will allow grunts in the field to use the sites the Pentagon itself wants to exploit. For a generation raised on the Web, any restrictions will damage morale, those people say.

“;What comes out of my blog is the experiences of a soldier right in the middle of all of this,”; Mud Puppy (a nickname for military police), who recently returned home to Illinois, wrote in a recent e-mail message. “;I think that people need to hear from us, more than they need to hear from the big whigs. War has a cost, and that cost is paid by soldiers.”;