PageRank is an algorithm used by Google Search to rank web pages in their search engine results. It is named after Larry Page, one of the founders of Google. PageRank was designed as a way to measure the importance of website pages. Originally, PageRank worked by counting the number and quality of links to a page 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. It is not the only algorithm used by Google to order search engine results, but it is the first algorithm that was used by the company, and it is the best-known.
The PageRank system is based on the dendritic structure of the internet, which takes into account the hierarchy of websites. It interprets a link from page A to page B as a vote, by page A, for page B. Votes cast by pages that are themselves "important" weigh more heavily and help to make other pages "important." Thus, a complex calculation of reciprocity is involved. In its most basic form, PageRank is expressed as a series of iterations whereby a page's ranking is determined by the sum of the ranks of the pages that link to it, normalized by the number of links on each of those pages.
Technically, the PageRank of a specific page is derived from a probabilistic scale of 0 to 10, where higher values correspond to greater importance. The PageRank of a page is calculated using a recursive algorithm that involves the PageRank of other pages linking to it, divided by the number of outbound links on each of those pages. This calculation involves several rounds of analysis to stabilize the PageRank values across the entire web. Google updates the PageRank scores regularly, but the frequency of updates has decreased over the years as the algorithm has become more complex and incorporates various other signals influencing search rankings.
Despite its historical significance, PageRank is no longer the sole criterion for determining the search ranking of a website, with Google using a more holistic approach that includes other factors like mobile-friendliness, page speed, and content relevance. However, understanding PageRank is crucial for SEO professionals and webmasters because it sheds light on how foundational linking structures influence website visibility. Moreover, the principles of PageRank, such as the importance of link quality over link quantity, remain relevant and continue to influence modern SEO strategies. In the ever-evolving landscape of search engine optimization, the legacy and intricacies of PageRank still resonate, reminding us of the foundational elements of digital connectivity and online authority.