I think the main responsibility that we all posses is that of respecting the person on the other computer. It's easy to forget that when you type messages and responses to other post you are writing that response to a person who has a certain belief or feeling towards an idea, after all blogging is a form of expressing oneself. The same goes for when we receive messages or comments on blogs. We have to take in to consideration that not every one has the same opinion as us and sometimes people have disagreements.
Blogs are a great way to express your feelings or ideas on a wide range of topics, and then share that expression with the world. People are going to disagree with you just as much as you will disagree with them. The only responsibility that we have is to respect each other disagreements.