You often see pleas for more politeness on the net.
I'd like to propose the converse: Try not to be so thin-skinned.
See if you can develop some more careful listening skills. Ignore the trolls, the flames, and the insults. Be slow to anger. Try and get your ego off of the table, and just look for any content (if any) in the argument and respond only to the content.
(And you know, often you can make your opponent look all the worse by "taking the high road", and remaining more calm and reasonable than they are. Letting an insult sit there unanswered shows just how little you think of it.)
And ask yourself... is it really all that polite to start lecturing hundreds of strangers about the importance of politeness just because you feel like one person has dared to dis you? I see this happen on technical mailing lists all the time.
Trust me, no one really cares that much that you feel insulted.
(And who needs a bunch of flies, anyway?)