PageRank

PageRank is a proprietary system used by Google to rate the strength, quality, and relevancy of different websites. While it is unclear exactly how PageRank is calculated, it can take into account your sites content, the frequency of updates, inbound links, and other factors. Pages are ranked on a scale of 0-10, with 10 being the best PageRank one could possibly achieve. As of this entry, there are debates within SEO circles that PageRank is still a major factor in SERP calculations by Google.