Does the DoD already use open source software?
Yes, extensively. The 2003 MITRE study, “Use of Free and Open Source Software (FOSS) in the U.S. Department of Defense”, identified some of many OSS programs that the DoD is already using, and concluded that OSS “plays a more critical role in the [Department of Defense (DoD)] than has generally been recognized”. Intellipedia is implemented using MediaWiki, the open source software developed to implement Wikipedia. This Open Source Software FAQ was originally developed on Intellipedia, using a variety of web browsers including Mozilla Firefox. Thus, this FAQ was developed using open source software.