What Is PageRank? Definition and Why It Matters

PageRank is the algorithm Google’s founders published in the 1990s to estimate a web page’s importance from the links pointing at it. Its central idea was simple and, at the time, new: treat a link as a vote, and weight votes from important pages more heavily than votes from obscure ones.

How it works, conceptually

Each page distributes its own importance across the pages it links to. A page that receives links from many other important pages accumulates importance itself, which it can then pass on through its own links. The calculation runs iteratively across the entire linked web until the values stabilise. No page’s importance is judged in isolation — it depends on the whole structure of who links to whom.

Why it mattered so much

Before PageRank, search engines ranked pages mostly by how often a keyword appeared on them, which was trivial to abuse by repeating words. PageRank added a signal that came from outside the page itself and was much harder to fabricate at scale, since it required other independent sites to actually create links.

PageRank today

Google stopped publishing public PageRank scores in its toolbar years ago, and the original algorithm has been extended and folded into a much larger, more complex ranking system. Link-based importance is still part of how Google evaluates pages, but it now sits alongside relevance, content quality, and signals about user experience — it’s one input among many rather than the whole system.

Third-party stand-ins

Because Google no longer shows a PageRank-like score, tools built their own estimates of link-based authority:

• Ahrefs’ Domain Rating (DR) and URL Rating (UR).
• Moz’s Domain Authority (DA) and Page Authority.
• Majestic’s Trust Flow and Citation Flow.

None of these is PageRank, and Google doesn’t use any of them in ranking — they’re independent estimates built from each company’s own link index, which is why the same site can show different scores in different tools (DR vs DA compared).

A worked example

Consider two pages that each earn a link from a new site. One link comes from a well-established news outlet that itself is linked to by many other important sites; the other comes from a personal blog with almost no other sites linking to it. Under the PageRank concept, the first link passes far more importance, even though both are, on the surface, “one backlink.” That asymmetry is exactly why link builders weigh source quality rather than counting links.

Why the original patent still shapes practice today

Even though the public toolbar score is gone, the reasoning behind PageRank still shapes how experienced link builders think. It’s why a single link from a well-established, frequently-linked-to publication is routinely valued over dozens of links from small, obscure sites — the underlying logic of votes-weighted-by-importance never went away, even as the specific implementation evolved into something far more complex inside Google’s systems.

What changed since the original algorithm

• Modern ranking systems combine link-based signals with many others, including content quality and user experience.
• Spam-fighting has become far more sophisticated, so manufactured links are identified and discounted much more reliably than in PageRank’s early years.
• Google has repeatedly refined how it handles link attributes like nofollow, treating them as hints rather than absolute rules.

Why the story still matters for link builders today

Understanding PageRank isn’t a history lesson for its own sake — it’s the clearest explanation available for why link building works the way it does. It explains why one link from a well-trusted, heavily-linked publication in your niche is worth more effort than ten links from obscure, unlinked sites; why internal linking from your own strongest pages matters; and why a link scheme built on volume rather than genuine votes from important pages tends to fail, because the entire system was designed to resist exactly that kind of gaming from the start. When a link builder tells you “quality beats quantity,” this is the mechanism underneath that advice — it isn’t just a slogan, it’s a description of how importance actually propagates through a linked network. It also explains why a brand-new site with no incoming links starts from close to zero in this model, regardless of how good its content is, and why the earliest links a new site earns matter disproportionately to everything that follows.

Common misunderstandings

• Believing a visible “PageRank score” still exists to check — it doesn’t, publicly.
• Treating DR, DA, Trust Flow or Citation Flow as if they were PageRank itself.
• Assuming link-based signals were replaced entirely by newer factors — they weren’t, they were supplemented.

Where to go next

Follow this into link equity for how the concept plays out link by link, compare third-party metrics via DR vs DA, or start from what a backlink is and browse relevant sites in the marketplace.

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Frequently asked questions