Keyword Use Has Changed
The first thing I want to stress is that keyword use has changed drastically over the past decade. At one point, all you had to do was stuff a page with a bunch of keyword phrases, and you could rank for a lot of those phrases. Sometimes you didn’t even have to use relevant keywords.
If you just repeated 100 different keywords twenty times each, you’d have a pretty good shot at ranking in the top 10 for at least a few of those keywords, especially with a little bit of extra effort like using heading tags or even hidden text (making the text the same color as the background).
Of course, search engine algorithms have gotten a lot more complex and a lot smarter. If you attempt tactics like that these days, you’ll probably just get your site banned from the search engines entirely. SEO requires a lot more subtlety these days. You cannot use all those shady tactics and expect to make it to the top, even for less competitive keywords.
Search engines are much smarter than they used to be with regards to keywords. For example, it used to be that if you wanted to rank on the first page for the keyword phrase “underwater basket weaving” you had to have that exact keyword phrase on your page multiple times. Now, it is possible to rank on the first page without having that exact phrase on your page at all. Of course, if you do have it on your page, you certainly have a better chance of ranking well.
Latent Semantic Indexing
However, other factors can push you to the top even if you don’t have the phrase on your page. There is also something called latent semantic indexing, or LSI. LSI is a complex process, but basically it involves the search engine’s system taking a look at a wide range of documents, comparing them to see which words they have in common, and determining relevance based not only on the individual page it is analyzing, but also those it believes are similar.
If you have “how to weave baskets under water”, Google would see that as contextually similar to “underwater basket weaving”. The search engine is a bit like artificial intelligence, because it can “learn” by analysing billions of pages for similarities, and it can figure out context by realising that many other pages that contain “underwater basket weaving” also contain the words “how to weave baskets under water”, and it realising those two phrases must be contextually similar.
Even though the search engine itself knows absolutely nothing whatsoever about underwater basket weaving, it is able to figure out what those pages are about simply because of how often words appear on other pages with the same groups of words.
You can learn more about LSI and what it means here.
Remember to keep in mind that just because you can rank well for a phrase that doesn’t appear on your page doesn’t mean you will rank well for that phrase. Therefore it is always better to have those exact phrases on your page whenever possible.
The most important thing to take away from this is that you do still need to have keywords on your pages in order for Google (and other search engines) to figure out what your page is about, but you no longer have to worry quite as much about incorporating specific keyword phrases or anything like that. As long as you research your keywords and include a few main keyword phrases on your pages, the rest will fall into place naturally.