The written word is incredibly powerful and in many cases not used to its fullest advantage. Online, putting things down in writing is most important as the web is completely information-driven. I'm not referring to hype or puffery, nor am I referring to the legal kind.
People are predominantly visual and they believe more what they see in writing.
One is to use written words, especially those of others. It's because they appear to be more objective and credible. Niche marketing is the trend of the future and people are leery of any statement made online. Therefore, you should if not must promote yourself as an expert in your particular field. And here's the kicker, which most web businesses neglect.