Weak SEO activity
This activity carries a low weighting in Search Engine Optimization. It may need to be carried out alongside other tasks in order to be fully effective. Read the text carefully for further details on how to SEO keyword density for maximum impact
Keyword density is the percentage of times a word shows up on a webpage. So if I have an article with 1,000 words and I mention 'car' 20 times then my keyword density for 'car' is 2% ... nearly.
Search engines also use Latent Semantic Indexing to see if a page uses words which mean the same thing. So 'automobile' can mean the same as 'car'. If I use 'automobile' 10 times in the example above then my keyword density for 'words that mean car' is 3%.
Search engines also consider the context surrounding the words. You can't just go through an article about orange juice and sprinkle in 'car' and 'automobile' expecting a search engine to say 'words like car appear most on this page so it must be a page about cars'.
Search engines aren't that simple anymore. They'll expect to see words related to 'car' to confirm the pages content such as 'door', 'speed', 'comfort', 'price', etc.
Its a hotly contested subject in the SEO community ranging from those who say it matters (include me in that) and those who say there is no connection to better rankings.
On top of this I've seen countless results with my own clients that makes me sure keyword density matters but that it is a fairly weak signal compared to other SEO activities.
Keyword density is one signal to search engines telling them what your page is about. It needs to be backed up by making sure the keyword is:
In other words search engines want to see that the page 'hangs together' in a comprehensive way that makes it confident that the content is really relevant to the keyword.
At the extreme is an activity known as 'keyword stuffing'. Use a keyword too many times and you can expect a penalty.
In reality a well written piece of text based on a particular keyword will have a density of between 2 and 4% (once you take into account words which mean the same) so that is where you should be aiming.
Making sure your text is easy to read however is far more important. A jumbled mess will have visitors heading for the back button sending a signal to search engines that you shouldn't be ranking where you do.
That said I often come across client pages where the keyword density is far too low and it can, without affecting readability, be increased with ease.
So when it comes to keyword density make sure you are in the ball park of 2-4%, not too far below and not too far above ... and then move on.
I'm Tim Hill, a Search Engine Optimisation and Online Marketing specialist. I created this site to help others understand that SEO is not a mysterious black art!.
If your a newbie try the Getting Started in SEO page, otherwise feel free to dig around and learn more.