Google Webmaster SEO Starter Guide - Originally written for Google Employees to improve website performance with users and search engines. Related Terms: SERP - Search Engine Rank Position | PageRank (PR) - Named for Google Co-founder, Larry Page. The PR Scale of 0-10 rates a web page. In the past, rank was based on the number of high ranking links pointing to the website. Recently factors like relevance and quality have gained importance. This website's current PR rating: It would be great if you can provide comparative analysis of this tool with Google Keyword Planner. Since you’re using this tool so you can provide best comparison. One differentiation which I understood is that this tool works for yahoo and bing as well whereas Google keyword planner works only for Google but Google being a dominating search engine, gives the highest returns, so only this reason may not be enough to buy it.