Don't be rude. Don't swear at anyone. Don't swear about anyone. Don't be dismissive. Don't mock. Be polite.
Discussion is welcomed and encouraged, so long as the above rules are abided by.
If I think a commenter is being impolite they get one warning and then the comment gets deleted. Repeat offenders will be banned.
I hope that the above will not happen, as for the most part, people are polite and respectful of others, however I am aware of at least one instance where individuals have felt unable to comment due to snarking from other bloggers. Which I think is unacceptable.