More than Keywords: 7 Concepts of Advanced On-Page SEOhttp://moz.com/blog/7-advanced-seo-concepts
A simple, illustrated look at concepts collected from research papers, patent filings, interviews and experiments as to the signals search engines may examine to determine what your webpage is about.
The challenge with SEO today is we focus on optimizing only what we can measure. This worked okay in 2005 when the focus centered on keywords and anchor text. Today, we simply lack the sophisticated computing power to match what search engines compute. However, basic principals guide text analysis. Understanding these principals can help us build better webpages and potentially help search engines to better understand our content.
Full post here: http://moz.com/blog/7-advanced-seo-concepts