In "Using Web 2.0 as a Weapon" (Professional Notes, Proceedings of the US Naval Institute, February 2010), Lieutenant Randal T. Jones discusses how RSS feeds, blogs, Wikis and mash ups are being used by the military. The Lieutenant points to the US Army Knowledge Online (AKO) as an example of a secure intranet with RSS feeds and blogs. He cites the US intelligence Intellipedia as an example of a successful classified Wiki and the Army's Tactical Ground Reporting Network (TiGRNET) as a mash-up. I could not find any publicly available references to TiGRNet, but it may be similar to the Tactical Ground Reporting System (TIGR).
However, this use of technology is not all one sided. Later in the same journal, Norman Friedman ("Stealing Signals") reports that from 2004 insurgents in Iraq were intercepting video from US Predator UAVs and have been doing so in Afghanistan as late as 2009. What is not clear is why these signals were being transmitted unencrypted or if they were of any practical value to the insurgents. A few fleeting images from a UAV would be of little value. But Web 2.0 technology is now available to anyone with a smart phone and this could make scattered images of far higher intelligence value.