Entity Salience is understanding what a particular bit of text or content is about and it is heavily used by search engines like Google. When they master it fully it will change the search engine results dramatically. So what should you be doing about it?
Search engines, when crawling content, are trying to identify the entity or entities (the subject or subjects) on the page and from there, which one or ones are the most prominent (salient). The most salient entity on this page is the concept 'Entity Salience in SEO' but an entity could be a place, person, business, topic, etc.
Page's usually have multiple entities. I used Google in the first line of this content and Google is an entity.
Now let's just say I drop the word 'banana' in here and I also use it in my title tag, url and main heading (h1 tag). These are all strong signals to a search engine like Google that the salient entity (most important subject) is bananas. I could mention the word again here and there throughout the text. How would Google then know that the main entity of this page wasn't 'bananas'.
They do it by looking for words that should also be on the page. Here are some of the words I've already used that are connected with 'Entity Salience in SEO':
If this content was really about bananas there would be more related words like 'fruit', 'yellow', 'skin', 'pulp', etc. scattered throughout the text. Don't get me wrong, by using the word banana and banana related words I have actually reduced the entity salience of my phrase 'Entity Salience in SEO' but I haven't done enough (given the length of this text) to convince any crawler that bananas are the salient entity instead.
Salience is measured on a scale of 0 to 1. 0 means this page may contain reference to a particular entity but there is nothing at all to suggest it has any useful information about that entity.
1 means this page is almost completely and definitely about that entity and very little else.
A test in the Google Natural Language Tool for the text of this article up to the first subheading:
So despite this being a very short article Google can still pick up the main subject area and almost completely discount my fruity attempts to steer it otherwise!
And remember the natural language tool is a very simple analysis of text. It does not see my title as a title or my subheadings and so does not weight these (but Google in full swing does!)
But why did this text only score 0.16 for 'entity salience'. Because if this really were an article about entity salience alone I would be talking about tokenization, lemmatization, word dependency and all sorts of fun academic stuff. However we don't need to go there unless we're talking about very advanced SEO.
This article should not rank when someone is searching for 'entity salience' - it is a vast field in itself. It should rank for 'entity salience in SEO', and it has a balanced score for both of those terms ... so it does.
From the early days of the Internet search engines had to deal with spammers who tried to rank pages where they shouldn't and were often successful. You could search for 'pictures of kittens' and find half the top ten results were for gambling or adult content related websites.
Spammers would do it simply by putting the phrase 'pictures of kittens' in specific places such as the url and page title and a large number of times on the page itself. One way to achieve this would be to insert the phrase using white text on a white background so only search engines would read it.
To see through this search engines used a second major signal - who links to that page/site? If a lot of respectable websites about kittens linked to it this was a strong confirmation that the page's topic area really was 'pictures of kittens'.
Using backlinks to decide rankings has multiple issues:
With Entity Salience search engines will attempt to understand when 'better' content appears on the web and should rank higher than other websites even if that better content has a very weak or non-existent backlink profile.
As of 2019 the work of search engines in this area is fast gathering pace and we can expect it to change the way rankings work over the next few years.
While I've looked here at entity salience of one page or one piece of content search engines will also consider the entity salience of an entire website or of a section of a website.
At a site level it knows the salient entity of this website is SEO so it is giving the SEO part of my page 'Salient Entities in SEO' an extra boost. A website about SEO with an article on entity salience in SEO should rank highly for 'entity salience in SEO' ... and it does.
And when a search engine truly understands entity salience backlinks become far less important as a ranking signal.
If you want a page to rank for a particular term you have to make sure search engines see it as the salient entity and that it is more salient than your competitors.
This page has always been here on my How to SEO website but it ranked on page 4 or 5 of the search results. I completely rewrote it so the content all worked to be the salient entity ('Salient Entities in SEO') or to reinforce that entity. Within a week I was at position 4 with no change in the number of backlinks.
That gives you some idea how much weight Google is already giving to this strategy and how you can use it to have a big impact on your rankings. Serve rich, deep content up to Google on a plate and it will find it hard to refuse you a place at the top table.