I fully agree with having a general philosophy that encourages the less civil folks to seek out existing venues like Reddit instead.  Having seen that behavior on both those platforms (and yeah, I get pretty ugly on twitter myself when riled up--I know, and I'm working on it), it can definitely stay there.  I am cool with that.

From a more practical perspective though, how does one enforce the CoC, and who decides what is what?  Seems like you'd need a reporting system and a dispute resolution system.  YouTube has perpetual fun with that idea, so I am not sure what the best approach is.  What are you in a position to offer and how much of it can you automate to ease the workload? 

Thanks to this group for the enlightenment around this subject too.   :)