Google's algorithm is a trade secret that the company does not fully disclose. However, we do know that the algorithm is designed to rank websites in search results based on many factors, including relevance and popularity. Relevance is determined by the content on a website and how well it matches the user's search query. Popularity is measured by things like the number of inbound links and social media mentions. The algorithm is constantly changing and evolving, which is why SEO is an ongoing process.