In other states I would check to see if the state already has guidelines set up.
John Sonnenberg, EdD CETL
34409 N. Circle Dr.
Round Lake, IL 60073
Dissertation: Educating Incarcerated Youth in Illinois: A Blended Learning Model
The State of Washington's has specific guidelines about retention of email and other resources.
These are just two links to a long list of guidelines and best practices for retention of email and social media tools, in general.
Chief Technology Officer
"A pessimist sees the difficulty in every opportunity. An optimist sees the opportunity in every difficulty."