Tableau Software knows just a thing or two about data visualisation. A spin out from Stanford, the company won the CODiE award for best business intelligence solution 2008... it's amazing what the faculty of visualisation can do for your intelligence, or your PR as anyone who has followed my obsession with data visualisation in public relations will know I believe. (Previous posts on the topic appended.)
Tableau Software's Niels Hoven has posted about using visualisation techniques (and a nifty Excel plug-in from Microsoft) to delve into the content of rival websites to determine keyword effectiveness and make your final keyword selection. He even rounds off by employing visualisation to measure the effectiveness of your SEO work. Nifty.
All round interesting post and a worthwhile read for SEO hobbyists and pros alike.
My related posts of yore: