PageRank is an algorithm used by Google to rank websites in its search engine results. It was named after Larry Page, one of the co-founders of Google. PageRank works by counting the number and quality of links to a page to determine a rough estimate of how important the website is. The more important the website is, the higher it will rank in search engine results. Google's original PageRank algorithm was based on academic papers written by Sergey Brin and Lawrence Page, the co-founders of Google. However, over time it has been improved and tweaked by Google's engineers to better reflect real-world usage patterns. There are number of factors that go into PageRank, but links are still the primary one. The more links a website has pointing to it, the higher it will rank. But not all links are equal. Links from high-quality websites (such as BBC.co.uk or Amazon.com) are worth more than links from low-quality websites (such as link farms or content farms).