Keyword Density and SEO

Published on August 3rd, 2009 by Mitchell Harper

It still surprises me how so many people see SEO (or Search Engine Optimization) as some sort of mystical witchcraft which they feel is best left to be managed by an in-house SEO super-guru or outsourced to an SEO company. To be honest SEO isn’t really that complex.

Like most things it’s actually fairly easy to implement – it just takes a bit of knowledge, patience and the willingness to get dirty with HTML. When it comes to getting started, there’s the basics like making proper use of heading tags, giving images alt tags, making sure your keywords come up near the top of the page, etc. All of these contribute and warrant their own posts, but today I want to talk about keyword density.

Keyword density is a fancy way to measure the number of times the keyword/keywords you’re trying to rank for in the search engines appears as part of the content of a web page. For example, if I was trying to rank for pizza and the entire contents of my web page was I like pizza because pizza tastes good, then my keyword density would be 28% (pizza appears twice in a total of seven words and 2 divided by 7 multiplied by 100 is 28.57%)

Using a tool such as Aaron Wall’s excellent (and free) keyword density analyzer, you can type in the location of a page on your website and see how you’re currently doing in terms of keyword optimization. Let’s take a look at the keyword density of Zappos.com and see if we can find some relationship between keyword density and SEO rank:

We can see that their first 3 keywords are:

• shoe (4.17%)
• shoes (3.23%)
• zappos (2.56%)

… and if we do a search on Google for any of these 3 keywords, of course Zappos.com is the first result. Now keyword density isn’t the only factor at work here – it’s just one of many. Zappos.com are extremely well known and have built up a lot of good will with customers, but keyword density helped them rank well in the early days. Zappos’s top 3 keywords have a density rank from 2.56% up to 4.17%, so what should you aim for?

2.5% – 5% is a good rule of thumb. If you’d like to see the keyword density of your competitors, then just use the keyword density analyzer and type in the location of their website. Generally you should focus on the home page if they sell one product/product category, or on the particular product’s page if they’re an eCommerce retailer with different products like Amazon.

Determining which actual keywords you want to rank for is also important. Generally if you’re just starting out in an extremely competitive space (such as selling shoes online or even ecommerce software ) then you’ll want to move further down the longtail of search. This means that instead of focusing on the #1 keyword which will drive 1 million visitors to your site, instead focus on the #20 keyword which will drive 5,000 – and then work your way up one at a time.

Google’s keyword tool is a great place to start. Just type in the most popular keywords relating to what you’re trying to rank for, and then sort the list by local search volume. Sticking with the Zappos.com example, here’s what I get when I type in shoes:

You can see that shoes gets searched for over 100 million times in a month, which would be incredibly difficult (if not impossible) to rank for. Instead, cast your eyes all the way to the bottom of the list:

The phrase expensive shoes gets 27,100 searches per month and is a lot more targeted than the generic shoes keyword. If you look at the SERPs for expensive shoes, you’ll notice that none are explicitly targeting the term in their page titles or descriptions:

Most results are also more editorially focused, meaning they are once-off posts which are generally easy to displace in the SERPs because:

• No one is making sure they stay in the top of the SERPs
• Their website’s aren’t explicitly focused on expensive shoes

So in this brief example, I would start out trying to rank on the front page of Google for expensive shoes. If I did this research before I bought my domain name, I might even register expensive-shoes-new-york.com or something similar to further boost my chances.

When it comes to building keywords into your page content, the #1 rule is to not sacrafice the readability of your content. Going back to our expensive shoes example, instead of using

We make it easy to buy expensive shoes online because when you buy expensive shoes online you should choose Acme

… as our META description, we’d use something like

Expensive shoes don’t have to cost the world! Get all of your favorite expensive shoe brands including DKNY, Versace and Armani at up to 50% off!

This sentence has context and the supporting keywords tell the search engines more about our website (in this case, the brands we sell).

For a more general overview of keyword placement, you’ll want to include your keywords in these parts of your document:

• The title tag of the page
• META description (this is used by Google to show a summary of your website in the SERPs)
• META keywords (arguable as they’re generally no longer used/factored in by all of the major search engines)
• Header tags, especially the <h1> tag which should be as close to the top of the document as possible
• Alt tags for images, such as <img src=”image.jpg” alt=”Your keywords here” />
• Any text that has a style emphasis, such as a <strong> (bold) or <em> (italic tag)

When you’re adding keywords to your web page’s title tag, keep keyword proximity in mind as it seems to play a big role in Google determining which positions your website should rank for. I say seems to, because no one really knows exactly how Google calculates relevance – we can only speculate, test and re-test.

Anyway, that’s just a quick look at one of many strategies you can use to outrank your competition in the search results. I’ll discuss other techniques in future blog posts, but if you have any questions please feel free to leave them as a comment.