Seth Godin shares a lot of good advice for business owners at Seth's Blog on how to communicate.  Today he gives some good advice on how NOT to communicate, by listing effective ways to lose an argument online.  For example, Tip#1:

Have an argument. Once you start an argument, not a discussion, you've already lost. Think about it: have you ever changed your mind because someone online started yelling at you? They might get you to shut up, but it's unlikely they've actually changed your opinion.

And #4:

Question motives. The best way to get someone annoyed and then have them ignore you is to bypass any thoughtful discussion of facts and instead question what's in it for the person on the other end. Make assumptions about their motivations and lose their respect.

For the full list, and Godin's ideas on what actually works, click here.