Good manners and the web (NETtiquette)

I think it's important to have good internet manners because the internet is available to millions of people worldwide. Everything you do, post, say, upload, and type is there for parents, peers, businesses, and colleges to see. If you wouldn't do something in person then why do it on the web ? If you portray yourself as an unmannerly person on the web then people may mistake you to be such a person real life.