Never thought I'd need one but what the heck.
Better to have than not I always think.
I think its common sense to suggest something resembling the Golden Rule, but not everyone wants to be treated nice (perverse, I know).
1. Nothing to get anyone sued.
2. No personal information unless it's yours.
3. Don't steal.
4. Nothing racist or obscene. I can deal with a potty mouth, but is it really needed?
5. No spam, ever.
6. No threats or personal attacks, speak to the issue not the person.
Otherwise, pretty much anything goes. Especially at me. PLEASE feel free to trash my work.