When Larry Page and Sergey Brin founded the Google search engine, their core insight was implemented as the PageRank algorithm. Put simply, PageRank determines where a page should rank in the SERPs based on the PageRank of incoming links from other sites — it’s a recursive algorithm.

The higher the PageRank, the greater the assumed authority of a particular site. That authority can then combine with a keyword analysis of a page. Then, they use this combination to devise a ranking of pages in response to a search query.

Thus, PageRank is a proxy measure of authority. Google’s algorithms, in their early days and even now for the most part, couldn’t determine a page’s authority for a specific search query by just looking at the content.

PageRank significantly improved upon previous methods, as early search engine users remember. However, it wasn’t perfect. This imperfection created opportunities for manipulating the system through various link-building tactics.

Keywords are at the heart of any SEO strategy. They are the thread that links sites to customers via their search terms. Over the years, people have focused and speculated a huge amount about how precisely to use keywords in on-page content to signal relevance to search engines and to rank well.

Historically, people have talked about keywords a lot, often focusing on minute details like “how many angels can dance on the head of a pin”: where to place them in the content, how many words should separate them from the start of a page or heading, the ideal ratio of keywords to other text, and so on.

Some (not very good) SEOs strive to produce content that contains an exact percentage of keywords, often with the result of producing content that isn’t very readable to humans. And some stick to the old tactic of writing as many pages as possible stuffed with keyword variants and synonyms to cover all possible long-tail searches.