One year ago I released the first version of our History of SEO infographic. This 2 page graphic was intended to collate various sources of historical SEO information about the search engines and the SEO industry into one easily digestible "cheat sheet", and since then many people have been asking if I'll be updating the History of SEO to include what happened in 2010.
The answer, you'll be pleased to know, is "yes". Changes and additions include: a ranking factors chart and events timeline updated to include 2010; "Whatever happened to...?", the fate of 90's search engines such as Lycos and Excite; and more random facts for your entertainment.
This years version is very long (and I mean that literally). Use the scrollbar at the bottom of the graphic to look through the entire history or if you prefer you can click on the graphic to launch it in a separate window.
Copy and paste the following code into your site if you'd like to share the graphic with your own readers:
So what happened to SEO in 2010?
Looking at the ranking factors chart for last year you'll see an increase in the importance of on-page SEO during the course of April and May coming at the expense of domain authority, and over the whole year a gradual decline in the importance of anchor text which has been compensated by what we're calling "user signals". What's going on here?
The answer can be found in the timeline events for last year. In April Google added Site Speed as a factor to it's algorithm then in May the May Day update that negatively affected sites with substantial amounts of duplicate or low value content. Both of these updates meant webmasters now have to pay much more attention to how their pages are built and the content that goes on them. May Day was widely seen as a chance to give smaller sites a chance to shine, hitting large sites that relied purely on domain authority for their rankings (along with cookie cut or recycled content), which is why the increase in on-page SEO is offset by a decrease in the relative importance of overall domain strength.
Meanwhile, the once-dominant factor of anchor text (specifically anchor text that matches a search query exactly) has gradually waned as we've seen search engines put less and less emphasis on it over time while inevitably paying more attention to user signals such as click through rates, bounce rates and other on-site behaviour, as well as citations and discussion on social media. In many ways this is a natural evolution considering that anchor text citations have been used by search engines as a proxy for real user data, and as they get access to more and more of this user data one conceivable future could be that links become redundant (in all their forms of importance: PageRank, Anchor Text, Domain Authority and Link Context). We're not there yet, however, and as we start 2011 links in our estimation ultimately make up most of the search engine algorithm pie chart, which currently looks like this: