At the bottom of this post you’ll find two (me thinks) classic infographics about Search Engine Optimisation (SEO). They were made by Search Engine Marketing agency Greenlight in London.

These infographics show you in the glance of an eye what became more and less important in SEO over the years.

Without going into too much detail about all these different factors, I want to highlight one obvious and quite major change: the shift towards trust.

More links Vs Better links

The second infographic (2002-2009) shows a decrease of the importance of PageRank and an increase of the importance of Domain Authority.

PageRank is the principle Google uses to determine how important a page is compared to other pages on the web. It mostly looks at the number of links a webpage gets from other websites. In addition it looks at the quality of the links.

This is where things get a little shaky. What exactly are quality links?

In a nutshell it means that a link to your website (aka inbound link or backlink) from a so called ‘high authority’ site is worth more than a link from a website with ‘low authority’.

Google knows that high authority sites such as e.g. The Washington Post, Wikipedia or Oxford University publish great content. Google trusts these sites. So, when people search for stuff, the web pages of these sites are likely to rank higher than web pages of other sites.

Can you touch Trust?

Amongst SEO experts there is a lot of talk about a principle called TrustRank. But Google has never confirmed that they actually have something like that as a separate measurable entity. I personally don’t think they do. Also ‘Domain Authority’ is not one fixed thing that you can actually measure.

What Google does is look at the combination of many different factors to determine quality of content and ultimately ranking of web pages. They look at the how long your domain has been around, how long it is still registered for, how close you are to a high authority site (in terms of linking), the number of links to your entire domain (domain-wide, not just home page), in what context your links are getting referenced (link-context), if your content is shared on Twitter and by who (user signals), and so on.

How to build Trust with search engines

My advice is: don’t get too caught up in SEO tactics. Yes, On Page SEO is important. Getting links is also important. But these are not strategies to build Trust with search engines.

So, to end this post, let me give you 3 examples of strategies that do build Trust with search engines:

1. Publish or be damned! By contineously publishing great content you will get linked to, reviewed, shared, valued and… found!

2. Become a though leader: Share your knowledge. Start blogging. Answer questions that people have. For instance on Quora. When people value your answers, you are building Authority & ultimately Trust. Also by search engines.

3. Build your network in social media: Better than you saying you are to be trusted is others saying you’re to be trusted. And nowadays, the influence of Social Media on SEO is even a ranking factor.

Bargain!

The History and Evolution of Search Engine Optimisation (1994 -2001)

The history of SEO (part I)

The History and Evolution of Search Engine Optimisation (2002 -2009)
The history of SEO (part II)

Note: here’s a link to the History of SEO Infographic that also contains 2010 (PNG image)