I really like the recently published Ethical Principles of the W3C. They sum up a lot of what the Web should be:
"The web should empower an equitable, informed and interconnected society. It has been, and should continue to be, designed to enable communication and knowledge-sharing for everyone. In order for the web to continue to be beneficial to society, we need to consider the ethical implications of our work when we build web technologies, applications, and sites."