Every year Google makes adjustments to its search algorithm. The majority are minor changes however they do occasionally roll out a major update which can affect search results in a significant way. Despite the fact that they almost certainly improve search engine optimization, rankings can often be significantly impacted. As such it is important to keep abreast of any possible changes.
Although Google are reluctant to disclose exact details and dates about such algorithmic updates, it is often known that an update has been made either because of a leak or volatility spikes in search results. One update that was of particular significance was an algorithm that specifically targeted sites that lacked good E-A-T (Expertise, Authoritativeness and Trust). Many sites saw a demotion in ranking as a result.
This is one of the most important factors that can determine your positioning in search results. As such a very good reason to develop high quality, unique content with authoritative back links. You need to maintain a blog/pages that demonstrate expertise in a subject. Google published an extremely detailed guide on this subject which can be downloaded from here.
Below I detail what I understand are the main components to ensure conformity and increase your SEO ranking
Content on Page
A. The main content of any article should be prominently displayed and immediately recognizable. The terminology used for this is “above the fold”
B. In addition the nature of the content should be obvious .This is generally achieved through the page design, organization, use of space, as well as the choice of font, font size, background, etc.
Additional Page Content
Be careful that you do not distract visitors with ads and other peripheral content, either supplemental or sponsored. For example ads that float down across the content. In short it should be apparent what are ads and what is content either by explicit labeling or a clearly delineated design.It should however be made clear that monetization through adverts does not necessarily detract from the quality of page content. Indeed they can often contribute to a better overall visitor experience. Having said that it is important that you as a webmaster ensure that the quality of adverts displayed is good and in particular if they are being automatically posted to your page via an advertising network.
Expertise – If your site claims to be an authority on a particular subject ensure that the Author is indeed an expert in the topic. Formal qualification is not a requirement but experience or in depth knowledge is.
Authoritative – This is either based on recommendation by a known expert or an established reputation.
I think it goes without saying that you should never copy content, hide content, fill the page with spam, or add deceptive links. You will be penalized. These are considered the lowest quality pages and will be reflected in your website’s ranking.