emr,
Yes, you cannot photograph active runways unless permission is granted. Landscapes of a base are not allowed. Soldiers are off limits if they are Rangers, SF or otherwise covert. Some FOBs I don't even mention or have any pictures of because of the nature of who works there.
Its basically common sense. If I think I could use it against myself if I were an enemy I don't post it. Equipment I try to stay out of the interior or details like instruments of equipment inside. Outside of vehicles the Afghans see as they drive around out there.
I work with a UAV that I photograph but only what has been released and in the brochure online. Actual systems used to fly it I won't put photo's up.
I was a soldier at one time like many and would not want to give information away that could harm someone. With the ease of information flow today it's amazing what actually gets leaked out to public sources like youtube etc.
Incidentally I had the most exciting day of my life starting at 4am and didn't even think to grab the camera as I was more worried about staying alive. BBC has coverage as well as other news outlets. Being unarmed is NOT fun.
http://www.bbc.co.uk/news/world-south-asia-11118459
The report leaves out all details that I have access to. We are very lucky. I had a firefight that stopped multiple suicide bombers within 100 meters of my location. A bunch of incoming. And we were shooting more than I have seen to date to repel the attack with attack aviation directly overhead firing, outgoing mortars and mark 19 automatic grenade launchers along with plenty of small arms.