Many Webmasters and most SEO companies live and die by Google’s Pagerank. Though it seems to be derived from a magical formula, it is actually quite simple. The components of the Google PageRank equation are as follows:
1. Quantity & Quality links: The amount, quality of incoming links to back your website.
2. Linked words: The keywords or "Anchor Text" that is used by other sites to link back to your website
3. Relevancy of links. How closely the sites content is to your site, the closer the match the higher your potential Pagerank.
4. SEO. The quality and level of the Search Engine Optimization or Search Engineering completed on your site.
Most of these criteria are things you can control, some more difficult then others. Remember, if you are looking to hire an SEO company, you may want to first check their Google Pagerank. Companies with low or no Pagerank may not be able to deliver on the promise of top search rankings, you may want to think twice about hiring such a firm.