What is PageRank?
PageRank is a link analysis algorithm that was developed by Google founders Larry Page and Sergey Brin in the late 1990s. It played a key role in the early success of the Google search engine.
PageRank is based on the idea that a link from one website to another can be viewed as a vote of confidence in that site. It counts the number and quality of links to a webpage to determine a rough estimate of how important the website is. The underlying assumption is that more important websites are likely to receive more links from other websites.
Specifically, PageRank interprets a link from page A to page B as a vote for page B by page A. It then assesses a website's importance recursively, by looking at the number of votes that are cast for it. Also factored into the equation are the number of votes that are cast by each voting page.
PageRank results can be displayed as a probability distribution used to represent the likelihood that a person randomly clicking links will arrive at any particular page. Values are typically on a logarithmic scale from 0-10, with the most valuable pages falling in the 8-10 range.
PageRank helped facilitate Google's rapid rise as a top search engine, as it provided more relevant results compared to competing search engines. However, in recent years, Google has started relying on other factors in addition to PageRank to determine search rankings.