When I was at Apple back in the 80’s, my roommate worked in the Developer Relations group, run by a fellow named Dave Szetela, who coincidentally is now quite an Authority in his own right on search marketing. Apple allowed you to have almost any title you wanted on you business card, and one of my roommate’s coworkers chose the title “Question Authority” which was a great double entendre, because this person was an authority on answering questions, and was also encouraging people to question authority in a 60’s-like fashion.
In that spirit, I’d like to encourage people to question the concept of “Authority” in SEO.
Google discloses on their web site that they use over 200 signals in their organic ranking algorithms. The most well-known of these is “PageRank”, which is based on a patent and now-classic paper  by Google’s founders Brin and Page (the name PageRank was a great choice, it rolls off the tongue much better than BrinRank). Although some in the SEO industry in the past claimed that PageRank determined upwards of 60% of a page’s organic ranking, more recently cooler heads have been prevailing and numbers in the 20%-37% range are being thrown around (25% sounds pretty reasonable to me based on anecdotal experience).
Another well-known concept that many suspect Google uses is the concept of “TrustRank”, which is based on a classic Yahoo paper . Instead of seeding every page on the web with a tiny bit of PageRank and then flowing PageRank around through iterations, TrustRank instead counts how many “hops” you are from trusted sources. One approach could be to identify 500 or 1000 trusted sites, then count hops; another could be to seed those trusted sites only in a PageRank fashion and see where the PageRank flows and settles. Another interesting concept is “Anti-TrustRank”, again disclosed in a classic paper  by some Stanford folks, where your website, or page, is penalized for being too close to “bad neighborhood” sites. No one knows for sure if Google is using TrustRank or Anti-TrustRank, but it seems possible.
There are many other signals people speculate about constantly, but one that really irks me is the concept of “Authority”. This is a loaded word and means different things to different people.
Some talk about “Domain Authority” as possibly being a domain-level version of PageRank. Usually by this, people mean “the moment this page is indexed, it will rank well simply because it’s on a website that has a lot of Domain Authority, regardless of external links”. However, it’s hard to see how that would be different than PageRank. This could simply be the result of an automatic flowing of PageRank from the existing site to the new page through whatever links are on the site, when the page is indexed. An example would be a brand-new Wikipedia article immediately ranking #1 for something, with no external links.
I do like, and see value in, SEOMoz’s concept of “Domain Authority”, which attempts to emulate as many of Google’s non-query-specific ranking variables as possible. Although it’s complex, based on many variables, and not completely disclosed, it does make sense to try to encapsulate everything about a page or a domain that makes it a strong player, without taking any particular queries into account, so pages/domains can be measured against each other on an apples-to-apples basis. I prefer to think of this as “Strength” rather than “Authority” however, since in the offline world, the word “Authority” tends to involve limits and jurisdiction that define and scope power, not just strength.
Others talk about Authority as being relevance-oriented, i.e. “wow, the National Chimney Sweep Guild is a huge authority on Chimney Sweep Ethics , and if I get a link from them to my website, that will help me rank for the term [chimney sweep ethics violations san diego]”. Google certainly has patents where they talk about categorizing queries; they talk about flowing relevance through anchor text (which may be as simple as prepending anchor text into the beginning of the document before indexing, possibly multiple times in order to weight the anchor text more heavily).
But if this relevance-oriented type of “Authority” were in place, would the National Chimney Sweep Guild be considered an “authority” on acne treatment? One would hope not!
On the paid search side, your Quality Score for a given keyword is partly dependent on the top organic queries your site tends to rank for, and how related those queries are to the keyword and creative. Google is very likely characterizing web sites by summarizing them with a snippet of text representing the top queries. It could be that such a snippet, if relevant to the anchor text, might flow along as well on the organic side of things, although it’s hard to imagine how such a process might work.
Is it really true though, that if you have a choice of two links, identical in PageRank and Anchor Text, one from a car audio website, and one from the National Chimney Sweep Guild’s website, that you are better off choosing the National Chimney Sweep Guild if you’re trying to rank for [chimney sweep ethics violations san diego]? I have not seen convincing evidence that this has been proven either way in this industry, and welcome any comments to the contrary (and forget about debating the differing amounts of traffic each link will bring, the value of users perceiving the Guild as an authority etc. – I’m just talking about the search engines’ ranking algorithms here).
The bottom line is – there is no paper, or patent on “Authority” from any of the search engines that is a smoking gun the industry can use to rally around a universal definition of “Authority”. So if you hear anyone talk about “website X has a ton of authority”, or “website Y is a huge authority on coconut headphones” – Question Authority. And don’t forget to Anti-trust anyone over 30.
P.S. Hopefully Dave Szetela will link to my posting; he’s a huge authority on search marketing…