Recently, I received an email question wanting to know about keyword density, asking questions like how do I deal with it, is it still a factor, and how important is it. As with most things in SEO, the answer is … it depends…
Sherman, set the Wayback Machine to the Interwebz circa 2001 …
Page rank was the big magilla in the ranking algorithm. It didn't matter how crappy your website was–with enough links from anywhere, you could get a page to rank. Trust and authority where unknown concepts in SEO. If you had a moderate to low competition KWD, you could rank without the word being on the page. If your KWD was moderate or harder you did need some on page SEO, and keyword density WAS a factor. At the peak of this zaniness I remember reading posts about the optimal keyword density being between 4.9% and 12.2%. The word had to be in the first sentence, had to be in italics once on the page, in bold once on the page, and in bold and italics once on the page. While not entirely true, there was a kernel of truth to be had somewhere in there.
Then in the fall of 2003 the shoe dropped. Google pushed out the Florida Update on a Saturday morning, and all hell broke loose. Trust and authority became leading indicators, and all those crazy keyword density formulas became the stuff talked about on the porch at the SEO old folks home. In short, the right anchor text from a trusted source could make a page rank even if the word wasn't on the page. Copywriters who loved superfluous wordy adjectives reveled around the bonfire with high value link sellers. Of course things changed over the next few years, but people cling to old ideas, especially if they love them or if they make their lives easier or more enjoyable.
Back to the question: does keyword density matter … kinda. If you want to rank for the phrase [fuzzy blue widgets], you had better have the phrase [fuzzy blue widgets] on your page. In fact, it should probably be the keyword on your page with the highest density (excluding stop words).That said, you shouldn't stuff the words [fuzzy blue widgets] on your page to the point where it becomes awkward to read. While I hesitate to give a number, if you have a keyword density that approaches or goes over 10% you should probably give it to a non SEO to make sure it reads like natural language. That's not to say you should never do it but, if you do, have a damn good reason and make sure it passes the sniff test.
How do I check keyword density? I use the Scribe SEO plugin (see Scribe SEO Review). Scribe SEO is paid tool that does a few things, and one of them is checking keyword density right from the WordPress post panel. It's incredibly easy to use. Before I publish a post, I run Scribe and check that the word/terms that I want to optimize for are the ones that have the highest density. I've been using it for several months now and am very happy with it. Here's a screen shot of what it thinks of this post:
No discussion of keyword density would be complete without touching on LSI (latent semantic indexing). You can read about LSI in lots of places on the web but, simply put, it's Google ability to understand synonyms–i.e., that [cars] and [automobiles] are the same thing. While Google says they aren't using LSI and I agree, I do have to say that something similar to LSI is definitely at work. My proof? Do a keyword search for [mike gray]. The word [mike] never appears on my website, but Google ranks me for the term and highlights the word [michael], so they have some some idea the words are connected. However, in actual practice, I don't see this all that often in the wild.
So what are the takeaways from this post:
- While keyword density isn't a primary factor, it isn't something to be ignored
- Make sure you are emphasizing the keywords you want with a KWD density tool
- Scribe SEO provides keyword density inside the WordPress post screen
- If you have a high density, make sure you are doing it while still sounding natural
- Don't depend on Google to use LSI or understand synonyms, even though they may be trying to