Placing important keywords in the content of your webpage is SEO at its most basic— one of the foundational blocks upon which SEO practices are built. But in the past this practice has led to many an awkwardly-written webpage, since many people have simply written content that has nothing more than keywords strung together with average-to-poor writing.
Nowadays, however, Google and other search engines have more powerful tools and algorithms at their disposal, many designed with the goal of finding and encouraging better-written content across the internet. Some of the ways that Google searches out quality content include:
TF-IDF: Term frequency-inverse document frequency
TF-IDF rates words and phrases by how often they are used. For instance, the word “car” appears more often across most documents and webpages than the term “car repair.” Having a more unusual word for your keywords can help improve your SEO.
Synonyms and Close Variants
Google knows how to recognize and connect words with their synonyms. For instance, it can identify that “car,” “automobile,” and “vehicle” belong together when they’re used in a single page or document. Content that uses a variety of synonyms for their keywords will be better optimized than content that uses the exact keyword over and over.
Not all portions of the page are created equal. Some are considered more important than others, and having good keyword use in these more important sections will improve your page’s SEO. How can you tell what’s most important? Well, for starters, you can compare your page with your mobile page (which you really need to have). Notice how mobile pages tend to pare down the main site to a header and main body text? For Google, that means those sections must be the most important.
Semantic Distance and Term Relationships
This one gets a little more complex. We’ll sum it up this way: Google can identify terms that are connected to one another by measuring where the terms are on the page in relation to one another. Still with me? Words within the same paragraph are more likely to be connected; words in the title and headers are likely to be connected with any words in the section below them. What this means is that a well-structured document or page— one that shows logical organization and forethought— will be better optimized than content that’s messier.
Co-Occurrence and Phrase-Based Indexing
Google also indexes pages based on phrases that are likely to occur together. So if you have the keyword “US Presidents,” Google would expect your document to contain related phrases (“election,” perhaps, or “Washington,” “Abraham Lincoln,” or “White House”). If your content doesn’t seem to relate to your keyword, then Google might rank your page lower.
How can you apply all of this to better optimize your page? It’s actually very simple: write well. Write like your teachers encouraged you to in school— with introductions, logical arguments, and conclusions. Think a little less about specific keywords and more about themes; why do you have the keywords you have? What ties them together? Try to answer questions that your audience might have. At the end of the day, Google is simply trying to encourage people to write clear, well-thought-out content that other people will want to read.
For a more in-depth look at these topics, check out this post from Moz.