From the research I've done into defamation..
The absolute defence of defamation is truth. If the statement is true, then there's no case.
Otherwise it becomes a measure of if the statement was opinion or not, and if it wasn't opinion and was harmful to their reputation or whatever they call it then it's defamatory.
In Canada damages don't have to be proven, damages are assumed.
The email thing though is interesting, but I think even a private email if harmful to someone's reputation and untrue could be defamatory (ie the coach lost his job and was blackballed or something).
http://www.duhaime.org/LegalResource...ation-Law.aspx
Another one, a bit better IMO
http://www.adidem.org/articles/DS5.html
Anyway, here's some useful links I found while researching this: