Law enforcement agencies without a comprehensive social media policy are behind the times but not so much from a technological sense as from an employment law or human resources management perspective. I have lectured in this area and helped draft policy yet I am still never surprised to find many agencies without a basic policy in place. Policy and training of staff are essential to minimize social media incidents that may damage a department's community standing and jeopardize an officer's employment.
Below are links to articles in a two-part PoliceOne series on social media risk to law enforcement:
http://www.policeone.com/police-technology/articles/6068508-Risky-business-Law-enforcement-and-social-media/
http://www.policeone.com/social-media-for-cops/articles/6087762-Risky-business-Social-media-and-your-job-security/