I'd have changed the title to communities because we agree on only one thing, or non-thing so we come in many stripes. But otherwise I like this statement linked below:
Having experienced scathing incivility at a blog that's moderated by someone who thinks it's okay to insult people, I'm rather skeptical of the success of this statement. Nice people will behave nicely. The rest make us look bad as a whole, rather than representing only themselves. They need to be reminded how to be civil. This statement is a good start.