How Websites Get Ranked by Importance
This patent describes a computer method for scoring documents in a linked database, like the internet, by considering the importance of other documents that link to them, helping search engines find better results.
Original patent title: “Method for node ranking in a linked database”
This patent describes a computer method for scoring documents in a linked database, like the internet, by considering the importance of other documents that link to them, helping search engines find better results. Granted to Leland Stanford Junior University in 2001 with 35 claims and 818 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
This patent outlines a computer method for assigning an "importance score" to documents within a network, such as web pages (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). It works by first obtaining a collection of documents where some link to others. Then, it calculates a score for each linked document based on the scores of all the other documents that point to it (Claim 1). For example, if a highly-scored website links to your blog post, your blog post's score would increase. The patent also describes various ways to adjust these scores, such as considering how many links a linking document has (Claim 2) or even how likely a user is to access that linking document (Claim 3). This process helps in organizing and presenting documents based on their calculated importance.
The gap
What does this patent NOT cover?
- Does not cover ranking documents solely based on the words they contain, without considering incoming links.
- Does not cover ranking documents where the score is not influenced by the scores of other documents linking to it.
- Does not cover ranking systems that only count the number of links to a document, without adjusting for the importance of the linking document itself.
- Does not cover ranking based purely on user behavior metrics like clicks, unless those metrics are used to adjust the linking document's weighting factor (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 7).
- Does not cover ranking where a "random traversal" (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 10) does not assign rank based on how many times a document has been traversed.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The truly novel idea was to treat links as "votes" of importance, where a link from a more important page counts more than a link from a less important page. This recursive definition of importance, where a page's score depends on the scores of the pages linking to it, was a breakthrough for ranking information in vast, interconnected networks.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Google Search (PageRank algorithm)
Academic citation indexing (e.g., impact factors)
Social network influence scoring
Recommendation systems for linked content
Why it matters
The bigger picture
This patent describes the core principles behind PageRank, the algorithm that powered Google's initial success and revolutionized web search. Before this, search engines often ranked pages primarily by keyword matching, leading to easily manipulated and low-quality results. By using the link structure of the web to determine importance, this method provided a far more relevant and robust way to find information, fundamentally changing how people navigate the internet.
Filed
January 9, 1998
Granted
September 4, 2001
Market context
Who's building on this
Companies in this space
Google continues to build on and evolve the principles of PageRank for its search engine, though their current ranking algorithms are far more complex. Other search engines like Bing and DuckDuckGo also use link-based ranking signals, even if their specific algorithms differ. Academic researchers in information retrieval and network science continue to explore and refine graph-based ranking methods.
Market impact
This patent, and the underlying algorithm, created a new standard for search engine quality. It enabled Google to quickly gain dominance by providing significantly more relevant search results than its competitors, leading to a massive shift in online information discovery. It spurred an entire industry around Search Engine Optimization (SEO) and became a foundational element for how information is organized and accessed on the internet.
Claim 1 — Plain English
What this patent covers
This patent outlines a computer method for assigning an "importance score" to documents within a network, such as web pages (Claim 1). It works by first obtaining a collection of documents where some link to others. Then, it calculates a score for each linked document based on the scores of all the other documents that point to it (Claim 1). For example, if a highly-scored website links to your blog post, your blog post's score would increase. The patent also describes various ways to adjust these scores, such as considering how many links a linking document has (Claim 2) or even how likely a user is to access that linking document (Claim 3). This process helps in organizing and presenting documents based on their calculated importance.
The clever bit
The truly novel idea was to treat links as "votes" of importance, where a link from a more important page counts more than a link from a less important page. This recursive definition of importance, where a page's score depends on the scores of the pages linking to it, was a breakthrough for ranking information in vast, interconnected networks.
What it does not cover
- Does not cover ranking documents solely based on the words they contain, without considering incoming links.
- Does not cover ranking documents where the score is not influenced by the scores of other documents linking to it.
- Does not cover ranking systems that only count the number of links to a document, without adjusting for the importance of the linking document itself.
- Does not cover ranking based purely on user behavior metrics like clicks, unless those metrics are used to adjust the linking document's weighting factor (Claim 7).
- Does not cover ranking where a "random traversal" (Claim 10) does not assign rank based on how many times a document has been traversed.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
High impact
Citation count
40/40
Highly cited
Claim breadth
20/20
Very broad protection
Recency
0/20
Older than 20 years
Assignee scale
20/20
Major company or institution
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$72K – $230K
Midpoint $144K · expired or expiring · industry baseline
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
35 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Page, L. (2001). How Websites Get Ranked by Importance (U.S. Patent No. 6,285,999). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/6285999/google-pagerank
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Websites Get Ranked by Importance cover?
This patent describes a computer method for scoring documents in a linked database, like the internet, by considering the importance of other documents that link to them, helping search engines find better results.
Who owns patent US 6285999?
Leland Stanford Junior University owns this patent, granted in 2001.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 6285999 cited by?
This patent has been cited by 818 later patents that build on its ideas.
What problem does this patent solve?
This patent describes the core principles behind PageRank, the algorithm that powered Google's initial success and revolutionized web search. Before this, search engines often ranked pages primarily by keyword matching, leading to easily manipulated and low-quality results. By using the link structure of the web to determine importance, this method provided a far more relevant and robust way to find information, fundamentally changing how people navigate the internet.
What does this patent NOT cover?
Does not cover ranking documents solely based on the words they contain, without considering incoming links.
Same assignee
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