Phill Bradley posted about a new site Website Grader, which measures the marketing effectiveness of your website against "dozen different variables, including search engine data, website structure, approximate traffic, site performance, and others."
I tried Google in Website Grader and it turned out that the search engine scored higher than 95% of all the websites tested by Website Grader.
Website Grader also gives you a brief summary of your mistakes. For Google they listed absence of meta-keywords: "Though Google does not seem to place high relevance on meta keywords to determine the content of a website, other engines like Yahoo! may still look at these."
Website Gradrer is easy to use and I think that it is a good idea to run your site and see what the recommendations for marketing effectiveness are.