DHS has issued a new document (22 pp.) that provides guidance on the use of social media for community engagement; Sept. 2012. Basic information provided in a document with a dull title and a less-than-exciting format.
NOTE: the URL is rather peculiar and is giving some readers trouble. To be helpful, I have loaded a text file to this site, so you can Virtual Social Media Working Group Community Engagement
If anyone from DHS reads this, please take note of the problems identified.