Most people’s reaction—I’m guilty, too—is to smart off in return. Unfortunately, the internet makes it all too easy for us to spout off things we later regret. With the various outlets to express ourselves, we really must learn to watch those impulse replies. Not only do they often result in shame, they accomplish nothing. Except maybe to feed the trolls.
Don’t feed the trolls. If something makes you really angry, walk away. Shut off the internet, shut down the computer if you must, and take a breather. Decide if it’s even worth your time. Most things aren’t. If it’s something you absolutely have to respond to, wait. An hour, a day, a week, if that’s what it takes for you to calm down. Then open up your word processing program (not the comment or reply on the web site!) and write what you need to say. Read it. Walk away and read it again. If by now, you feel confident your words are strong and convey your message in a fashion that portrays your passion and intelligence, make it public.
You may still get trolled. People will almost certainly still disagree with you. But those same people will respect a thought-out answer and will hopefully reply in a thoughtful way as well. Everyone wins!