Content and keyword relevance (hint: look up hit-tail) the traffic really wants to see you focus on their needs not your PR. Page Rank may follow, once good relevant traffic patterns stabilize.
(This comment is part of the solution -- Mike Levin)
HitTail is a low-cost service that begins to work after you have logged, maybe, 100 blog posts or website entries and have begun getting search hits on them. It takes you through a process of identifying words searchers are using that you should be creating content for on your site. A search tool that strengthens content. Pretty ideal combination.
I've never been an advocate of keyword analysis either, taking natural search engine traffic as it comes. However, today I discovered HitTail which might have changed my mind.
HitTail HitTail reveals in real-time the least utilized, most promising keywords hidden in the Long Tail of your natural search results.This could lead to more traffic and more writing ideas.