I know a lot of bloggers that have to read and respect A Bloggers' Code of Ethics, specially the first item (Be Honest and Fair). It is a very great article, go read it and, please, try to use it. (via MetaFilter)

Integrity is the cornerstone of credibility. Bloggers who adopt this code of principles and these standards of practice not only practice ethical publishing, but convey to their readers that they can be trusted.