Who formulates best practices for social media in government?
In the U.S., there are several groups who establish governance for using social media for government communications and collaboration. Webcontent.gov provides general guidance. Web Manager University offers orientation for web professionals new to government practices vis a vis social media. The Web Content Managers Forum may have restrictions for membership.
In a quasi e-treaty, Estonia and Spain have signed a safer social networking agreement. The signatories pledged to advise the European Commission of their self-declaration and to explain how they plan to implement the provisions described in the agreement.
Read more about the principles here: http://ec.europa.eu/information_society/activities/social_networking/eu_action/selfreg/index_en.htm