Google’s Agent Rank / Author Rank Patent Application

Google returns results based upon content appearing upon individual pages, or at specific URLs. But that content could come from different authors, who have different levels of control over it. For example, a blog page may have posts written by more than one author, comments penned by others, and advertisements showing ads that even the owner of the site has no direct control over. A forum might have many different authors responding to an initial post, and may also display advertisements.

Imagine a system that instead of ranking content on a page level, breaks those pages down and looks at smaller content items on those pages, which it associates with digital signatures. Content creators could be given reputation scores, which could influence the rankings of pages where their content appears, or which they own, edit, or endorse.

That’s a broad overview of a new patent application from Google…

Agent rank

Invented by David Minogue and Paul A. Tucker US Patent Application 20070033168 Published February 8, 2007 Filed: August 8, 2005


The present invention provides methods and apparatus, including computer program products, implementing techniques for searching and ranking linked information sources. The techniques include receiving multiple content items from a corpus of content items; receiving digital signatures each made by one of multiple agents, each digital signature associating one of the agents with one or more of the content items; and assigning a score to a first agent of the multiple agents, wherein the score is based upon the content items associated with the first agent by the digital signatures.

Agents and Authority

When we perform a search at Google, we receive responses to queries based upon how relevant those results might be to our search terms. The order of those results is based upon rankings influenced by both query-dependent and query-independent criteria.

Query-dependent criteria are signals that try to identify how semantically related a document is to a query, such as word frequency distributions.

Query-independent criteria are signals that attempt to identify how authoritative, or intelligible, or trustworthy a document might be, such as PageRank. PageRank tries not only to look at the number of references to a document, but also the quality of those references.

Can authority or trustworthiness be measured in a different way, based upon understanding who the author of content on pages might be, through the use of digital signatures associated with an author? Could query-independent signals be tied to that author, so that a score for content created or controlled or edited or reviewed by the author could be used to rank pages?

This patent application describes a system where that might be a possiblity.

Agent Control of a Resource

The document begins by looking at how much control that agents might have over specific resources.

When all content from a resource is under the control of a single agent, the reputation of the agent can be directly related to the content of that resource. But, it’s possible that a page has more hands involved than one, that each control different parts of a page. In that case, if the different partitions of information can be indentified, reputation for each agent might be calculated at that partition level.

Difficulties involved with this approach might involve the fact that an agent may contribute content to many different resources, a single source may be created or controlled by multiple agents, and the ownership and control of a resource may change over time.

Benefits of the Approach

The patent filing describes a number of features and approaches, and they are worth looking over, but I want to focus upon the benefits that they say this will bring to us:

  1. Identifying individual agents responsible for content can be used to influence search ratings.
  2. The identity of agents can be reliably associated with content.
  3. The granularity of association can be smaller than an entire web page, so agents can disassociate themselves from information appearing near the information for which the agent is responsible.
  4. An agent can disclaim association with portions of content, such as advertising, that appear on the agent’s web site.
  5. The same agent identity can be attached to content at multiple locations.
  6. Multiple agents can make contributions to a single web page where each agent is only associated to the content that they provided.

Digital Signatures for Content

Different content pieces on a page can be signed with a digital signature, either directly by the agent or indirectly on behalf of the agent. These signatures identify who actually created each content piece on a page. One example for a method of creating and validating digital signatures is the World Wide Web Consortium’s XML-Signature Syntax and Processing

Content pieces can have multiple signatures based upon roles an agent may take involving the content, such as author, publisher, editor, or reviewer.

An agent would have exclusive access to the private key they use to sign the content piece, and the digital signature could also include metadata such as creation date, review score, or recommended keywords for search.

Agents could sign only a portion of a page, and exclude content over which they don’t claim any responsibility, such as ads served alongside the document.

That content can range from individual hyperlinks to entire documents, and can include text, images, audio, or video. The signature can also allow people to verify that the signed content hasn’t been materially altered since the signature was generated.

If you want to allow your content and signature to be portable, such as for a syndicated article, you could state that in the meta data associated with the content.

Ranking and Reputation Scores

Tying a page to an author can influence the ranking of that page. If the author has a high reputation, content created by him or her many be considered to be more authoritative that similar content on other pages. If the agent reviewed or edited content instead of authoring it, the score for the content might be ranked differently.

An agent may have a high reputation score for certain kinds of content, and not for others – so someone working on site involving celebrity news might have a strong reputation score for that kind of content, but not such a high score for content involving professional medical advice.

Reputation systems are often measured in terms of effectiveness by how difficult they might be to attack and manipulate. Here, there are at least two factors that may help keep manipulation from happening:

  1. Reputational scores may be set so that they are relatively difficult to increase and relatively easy to decrease, so that an agent may not want to place his or her reputation at risk by endorsing content inappropriately.
  2. Since signatures of reputable agents can promote ranking of signed content in search results, agents are provided a powerful incentive to establish and maintain good reputational scores.

The method of ranking based upon reputation scores is described in an analogy based upon PageRank. There’s also some discussion of an alternative possibility of using a seed group of trusted agents to endorse other content. Agents whose content receives consistently strong endorsements might gain reputation under that method. In either implementation, the agent’s reputation ultimately depends on the quality of the content which they sign.

The use of digital signatures enables the reputation system to link reputations with individual agents, and adjust the relative rankings based on all of the content each agent chooses to associate himself or herself with, no matter where the content may be located. That could even include content that isn’t on the internet.


This is a very different way of providing rankings for pages, based upon the reputations of agents who may have interacted with, and digitally signed content on those pages.

Ted Nelson, one of the early pioneers of hypertext, spoke at Google a couple of weeks ago (Transclusion: Fixing Electronic Literature – link to video). He described a very different kind of hypertext than what we are familiar with, which involved a system for connecting electronic documents with content from multiple sources appearing on the same pages together. The last question in the Q&A part of the presentation asked how his electronic documents might be connected so that they can be found easily. His answer, “I guess Google will do that.” This isn’t the system that Ted Nelson envisioned, but it shares some similarities.

I could see blogging systems building tools that allow for digital signatures like the ones described here, such as the Typekey feature in Typepad to authenticate the identity of commenters on multiple blogs.

Opinions expressed in the article are those of the guest author and not necessarily Search Engine Land.

Related Topics: Channel: SEO | Google: Authorship | Google: Patents


About The Author: is the Director of Search Marketing for Go Fish Digital and the editor of SEO by the Sea. He has been doing SEO and web promotion since the mid-90s, and was a legal and technical administrator in the highest level trial court in Delaware.

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  • Michael Martinez

    There are quite a few problems with this kind of system.

    First of all, reputation has never been a useful mechanism for evaluating quality of content on the Web. However, let’s assume that the mechanism itself is better than we have today.

    What is to keep people from simply copying reputable content from location A to location B (with the digital signature intact)? What would be required to produce digital signatures that validate only at the original point of insertion? What do you do if the site you contributed content to goes through a major redesign?

    Also, if you go with the “seed set” concept, there is an inherent and incurable flaw there. Who picks the seed set of experts, and how do you deal with the inevitable conflicts of opinion and bias that arise within communities of experts?

    Wikipedia cannot even build uniform communities of experts in its growing mob of biased opinions, but once it does get some experts involved they invariably become frustrated with the overwhelming naivity of the Wiki community and leave.

    Various forum packages already offer a reputation system now and it’s mostly a “here’s some rep for my buddy” system.

  • Bill Slawski

    All very good points, Michael.

    I do think that they provide some hints of things that they might try to do to address some of those issues, but those aren’t fleshed out in any level of detail.

    For instance, the application of a digital signature to a specific piece of content at a certain address may create meta data that shows where the content is located, and when. If the creator of that content doesn’t want that content syndicated, then other instances of the content might just be ignored by a search engine. Could that be manipulated? Maybe.

    I was left with a number of the same questions that you have, though.

  • Tony Comstock

    What about ideas, transmitted digitally, that do not yeild easily to language, or language based tools? Will this new app deal with them any better than what we have now?

  • Bill Slawski

    Hi Tony,

    The patent application does mention that non-text content, such as images, audio, and video can be digitally signed by agents (writers, editers, reviewers, etc.) and associated with those agents. I think that’s what you are asking about.

    We are only given a broad overview with the patent application, so it’s a little hard to tell what might be done with the system described here.

    Could it be used, for instance, to assign greater or lesser amounts of reputation to users who leave annotations regarding specific videos or podcasts or so on? Maybe. Or based upon the reputation of the creator of that video. Probably. Will those reputations be used to influence rankings of pages that content appears upon. It could.

    Will it be used? We don’t know. Possibly.

  • pittfall


    Could there be a way to assist this process? Signatures and comments are typically labeled in social websites like blogs, however, what about standard websites? Many of these would be considered experts, and be considered an important aspect of ranking. Are there any considerations for unknown authors?

    Very interesting topic!

  • Bill Slawski

    Hi Steve,

    The patent does address what might happen when there are no digital signatures associated with content on pages:

    If no digital signature associates an agent with a specific content item, the content item is associated with an owner of a location where the specific content is found and a score is assigned to the owner based on the specific content item.

    So, a digital signature isn’t absolutely essential to how agent rank might work, though it does look like it is important if information is going to be collected about different authors from the same page.

    If Google does attempt to implement this, it will be interesting to see how they try to inspire people to use signatures.

  • AndyBeard

    You walk into a bookstore and the material available is categorised in various ways, but they also have a top selling authors section, and a recent hits section.

    People have been signing their work in various ways on the internet for a long time. I sign my work with a link back to the original work on my own domain.

    Adoption of various forms of digital signature are becoming more widespread, and for example you can use things like OpenID combined with blogging comments.

    The invention seems too “obvious”

  • Bill Slawski

    Great analogy, Andy.

    To simplify the test that is used when considering granting a patent, the work in question must be “new, nonobvious, and useful.”

    I mentioned Ted Nelson’s work because this patent application echoes the idea that snippets of pages from other sources and other authors can be joined together in new documents, with references to the original sources and links to those that don’t go away and are trackable.

    Digital signatures, though not as widely used as they could be, through initiatives like OpenID also aren’t anything new.

    As I mentioned in my conclusion though, the answer that appeared to elude Ted Nelson, who has been working on something like this for decades, has been a way of tracking and ranking those content items across different pages and sites, and indexing pages based upon a reputation system.

    Is that aspect of this invention “new, nonobvious, and useful?” That’s going to be the task of the patent examiner to determine. That doesn’t mean that we can’t question it, like you have. But I do think that there are aspects of combining these many ideas together that are nonobvious even though parts of them may be.

  • Jonathan

    Although I’m reading the actual patent process and I’m not seeing anywhere that it claims it’s owned by Google. The inventors are yes, up in Mountain View, but where does it actually state it’s for Google?

  • Bill Slawski

    Hi Jonathan,

    It says that in the USPTO assignment database, which records assignments of patents and patent applications.

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