For example, PageRank, an algorithm developed by Google's founders, Larry Page and Sergey Brin, uses mathematical concepts and probability theory to rate and rank web pages based on their popularity and authority. Understanding these mathematical algorithms helps SEO specialists optimize content and improve visibility in search results. Each algorithm will be updated on a constant or regular basis as the Internet changes due to user preferences, the evolution of SEO-manipulative spam and the emergence of technologies that improve the user experience on websites. SEO best practices are changing rapidly, so fast that it's no longer enough to modify your SEO tactics to improve them a little.
For example, it's quite normal for an SEO agency to use several data sources or a single tool to conduct a website audit once a month. This means that SEO professionals were only able to agree in 1.3% of cases on what factors influenced SEO. While much of the SEO experience is based on best practices published in sources such as Google's webmaster tools, the way in which SEO consultancies operate is still too anecdotal and lacks statistically significant rigor. Much of today's SEO best practices are too generalized and don't take into account the complexities of the way content resides on sites Web.
