Various advice is available, but going out of date very quick as services change and new ones appear. Mostly this is common sense.
Important NOT to use your personal account – keep work activity separate.
http://www.nspcc.org.uk/Inform/cpsu/Resources/Briefings/social_networking_services_wdf69029.pdf
http://www.britishrowing.org/upload/files/Association/Welfare/BritishRowingSPCG31.pdf