Mine technical blogs/forums
Technical blogs and forums provide a way for technical staff to ask for assistance or troubleshoot problems. In doing so they may reveal information such as operating system (OS), network devices, or applications in use. 
Detectable by Common Defenses (Yes/No/Partial): No
Explanation: Cannot detect access to public sites.
Difficulty for the Adversary
Easy for the Adversary (Yes/No): Yes
Explanation: Success is dependent upon the existence of detailed technical specifications for target network posted in blogs/forums. Poor OPSEC practices result in an adversary gleaning a lot of sensitive information about configurations and/or issues encountered.
- Jeff Bardin. (2012, October 10). OSINT and Cyber Intelligence - Fun and Sun in Miami. Retrieved March 1, 2017.