PageRank
PageRank is Google's original way of judging a page by the links pointing to it, weighing each link by how important its own page is.
PageRank is the method Google was founded on for judging how important a page is from the links pointing to it. Each link counts as a vote, and a vote from a page that many others link to counts for more. Larry Page and Sergey Brin described it in their 1998 paper on the first version of Google.
It's why links became so central to SEO, and why so many people have tried to fake them.
How it works, roughly
Imagine someone clicking links at random across the web. Pages they keep landing on are important. A page gets more PageRank when many pages link to it, and more again when those pages are themselves well linked. Each page shares its score among the pages it links to, so a link from a page with few outbound links passes on more.
For example, say Kestrel Roasters' guide to grinding beans gets one link from a national newspaper's coffee page, which thousands of sites link to. That single link can be worth more than links from fifty small blogs nobody links to.
Does Google still use it?
Yes, in a much changed form. Google's guide to its ranking systems lists link analysis systems and PageRank among the many systems it uses, and says PageRank has evolved a lot since it began. The toolbar that once showed a page's PageRank score to the public went years ago, and no tool can show Google's real figure. Scores like domain authority are other companies' estimates.
PageRank and AI search
The idea behind PageRank, that pages others point to deserve more trust, still shapes which pages turn up in search results. And many AI platforms search the web before they answer, so the pages they read are often the ones that rank. That's one reason well-linked reviews and roundups appear so often among the sources of AI answers. What they say about you is still what decides whether you're named.