From Army.mil:
WASHINGTON (Army News Service, April 20, 2007) – Changes to the Army’s operations security regulation address accountability, new technology and the inclusion of all Army personnel in OPSEC practices.
The revised Army Regulation 530-1, “Operations Security,” provides updated definitions; aligns the Army’s policies, terms and doctrine with the Defense Department; and brings Army Contractors into the fold while addressing the role Army Family Members have in OPSEC.
“The change includes Army Civilians and Contractors, who are not subject to the Uniform Code of Military Justice,” said Maj. Ray Ceralde, the Army OPSEC program manager and author of the revision. “The reason we included Contractors in the regulation is they’re more involved in operations today than ever before. If you have all your Soldiers and DA Civilians practicing OPSEC and your Contractors – who are an integral part of your operations – aren’t … well, you have a gaping hole in security that could affect everyone’s lives.”
Maj. Ceralde said OPSEC is a “total Army concept” and includes Families and friends though he acknowledged they aren’t subject to a commander’s orders.
[…]Regulation changes also address how technology, specifically the Internet, has changed the face of OPSEC since the last major revision to the regulations in 1995. A 2005 revision addressed new technology, but the new revision addresses technological concerns not covered in the 2005 revision.
“The Internet, personal Web sites, blogs (Web logs) – those are examples of where our adversaries are looking for open-source information about us,” said Maj. Ceralde. “Open-source information isn’t classified and may look like nothing more than innocuous bits of information, a piece here, a piece there, like pieces of a puzzle. But when you put enough of the pieces together you begin to realize the bigger picture and that something could be going on.”
[…]
While Army personnel may maintain their own Web sites or post information on blogs, Maj. Ceralde said they have to be careful about what they write and what they post because even unclassified information can provide significant information to adversaries.
“For example, photos of deployed Soldiers to share with Family and friends are acceptable. However, when the photo includes a background of the inside of their camp with force protection measures in plain view, an adversary who is planning to attack their camp and sees a photo like this on the Internet now knows how to counter their force-protection measures,” Maj. Ceralde said.
You might be aware that this year’s 
The D-Ring 
