Anonymity in Internet

What about people who hide behind anonymity when they write comments in the internet?

In my opinion this is the dark side when you are empowered by the fact that you don’t have to be liable for your opinions.
I’m saying this because I met Jeff Jarvis from buzzmachine.com and Michael Arrington from TechCrunch.com and they told me that they are insulted every single day – and in the case of Arrington someone even spat on his face.

If we stood by our opinions, I think we should put our name next to it. However, if you go to any newspaper site and click on comments, you see that most people use nicknames in order to insult what people do.

So, I would like to hear your opinion on anonymity in the internet.