On 9 January 1998, Google registered the patent for its algorithm it used to rank web search results, on 2 June 2019, the Google PageRank patent has officially expired. This now means that the algorithm can now be used by anyone who so wishes to as Google can no longer claim nor enforce its rights to it.
The patent has expired because utility patents in the USA are set a a term of 20 years from the original filing date before they expire.
However, this is not necessarily a blow for Google or its search business as on 20 October 2015 the search engine founded by Sergey Brin and Lawrence "Larry" Page was granted a patent for its patent filing application for a new PageRank algorithm titled "Producing a ranking for pages using distances in a web-link graph."
"A method assigns importance ranks to nodes in a linked database, such as any database of documents containing citations, the world wide web or any other hypermedia database. The rank assigned to a document is calculated from the ranks of documents citing it. In addition, the rank of a document is calculated from a constant representing the probability that a browser through the database will randomly jump to the document. The method is particularly useful in enhancing the performance of search engine results for hypermedia databases, such as the world wide web, whose documents have a large variation in quality," reads the abstract of the original Google PageRank PageRank algorithm titled "Method for node ranking in a linked database."
What does PageRank actually do?
To put it in simpler words, PageRank is a method for determining which web page should rank higher based on keywords and other factors when it appears on Google's search results page. It derives its name from one of Google's founder's names, Larry Page.
"PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page’s value. In essence, Google interprets a link from page A to page B as a vote, by page A, for page B. But, Google looks at considerably more than the sheer volume of votes, or links a page receives; for example, it also analyzes the page that casts the vote. Votes cast by pages that are themselves 'important' weigh more heavily and help to make other pages “important.” Using these and other factors, Google provides its views on pages’ relative importance," reads a statement by Google explaining PageRank.
With so many new platforms where people can find and search for information on the Internet, is PageRank still necessary?
Short answer, yes.
The interesting part is how PageRank has become an important part of how we mostly, outside of social media, find information on the World Wide Web (WWW0. It also (fortunately or unfortunately, depending who you ask) means that the information you discover and get visibility of on the WWW, is mostly determined by Google, and not necessarily what is available out there.
If you want to learn more about the idea behind PageRank, read this Stanford University paper by Sergey Brin and Larry Page.