Kartoo is a visual meta search engine. The interesting thing about is the visual component that not only shows the circle of influence, but also shows the nature of that influence.
A search of our SEO lyrics contest, (Where by the winning, the winning lyrics could net a cool $1,000) delineates the influencers in the space.
And very informative if you take a moment to understand it's relational value.
Have a good one.
~The (SEP) Guy