RICHMOND, Va. — From the front lines of Iraq and Afghanistan to here at home, soldiers blogging about military life are under the watchful eye of some of their own.

A Virginia-based operation, the Army Web Risk Assessment Cell, monitors official and unofficial blogs and other Web sites for anything that may compromise security. The team scans for official documents, personal contact information and pictures of weapons or entrances to camps.

In some cases, that information can be detrimental, said Lt. Col. Stephen Warnock, team leader and battalion commander of a Manassas-based Virginia National Guard unit working on the operation.

In one incident, a blogger was describing his duties as a guard, providing pictures of his post and discussing how to exploit its vulnerabilities. Other soldiers posted photos of an Army weapons system that was damaged by enemy attack, and another showed personal information that could have endangered his family.

"We are a nation at war," Warnock said by e-mail. "The less the enemy knows, the better it is for our soldiers."

In the early years of operations in the Middle East, no official oversight governed Web sites that sprung up to keep the families of those deployed informed about their daily lives.

The oversight mission, made up of active-duty soldiers and contractors, as well as Guard and Reserve members from Maryland, Texas and Washington state, began in 2002 and was expanded in August 2005 to include sites in the public domain, including blogs.

The Army will not disclose the methods or tools being used to find and monitor the sites. Nor will it reveal the size of the operation or the contractors involved. The Defense Department has a similar program, the Joint Web Risk Assessment Cell, but the Army program is apparently the only operation that monitors nonmilitary sites.

Now soldiers wishing to blog while deployed are required to register their sites with their commanding officers, who monitor the sites quarterly, according to guidelines published in April 2005 by Multi-National Corps-Iraq.

Spc. Jean-Paul Borda, who has indexed thousands of military blogs for a site called Milblogging.com, said by email that the military still is adapting to changing technology.

"This is a new media — blogging. Podcasting. Online videos," wrote Borda, 32, of Dallas, who kept a blog while he was deployed in Afghanistan with the Virginia National Guard. "The military is doing what it feels necessary to ensure the safety of the troops."

Warnock said the Web risk assessment team has reviewed hundreds of thousands of sites every month, sometimes e-mailing or calling soldiers asking them to take material down. If the blogger doesn't comply with the request, the team can work with the soldier's commanders to fix the problem — that is, if the blogger doesn't post anonymously.

"We are not a law enforcement or intelligence agency. Nor are we political correctness enforcers," Warnock said. "We are simply trying to identify harmful Internet content and make the authors aware of the possible misuse of the information by groups who may want to damage United States interests."

Some bloggers say the guidelines are too ambiguous — a sentiment that has led others to pre-emptively shut down or alter their blogs.

"It's impossible to determine when something crosses the line from not a violation to a violation. It's like trying to define what pornography is or bad taste in music," said Spc. Jason Hartley, 32, who says he was demoted from sergeant and fined for reposting a blog he created while deployed to Iraq with the New York Army National Guard.

According to Hartley, the Army had forced him to stop the blog even before the oversight operation existed, citing pictures he had posted of Iraqi detainees and discussions of how he loaded a weapon and the route his unit took to get to Iraq.

Warnock contended that soldiers should not be discouraged from blogging altogether.

"Giving soldiers an outlet for free expression is good. American soldiers are not shy about giving their opinions and nothing the Web Risk Cell does dampens that trait," he said.

Matthew Currier Burden, 39, a former intelligence officer who wrote "The Blog of War," a collection of entries from bloggers who served in the war, said soldiers' Web sites can go a long way toward portraying positive aspects of the war and other "stories that need to get told."

But he said it's legitimate to fear that some information could be used the wrong way.

"The enemy knows the value of the blogs," Burden said. "The biggest thing that we fear is battle damage assessment from the enemy. We want to deny them that."