What is keyword density? Is it still effective today? How can I use it to manipulate my SERP's position?
For those not familiar with keyword density, imagine this. You have a website. On this website there is a specific page that you want to rank well. This page consists of 100 words. If 25 of the words on your website are keywords, you have a keyword density of 25%.
Keyword density was one of the first defining factors for indexing your page. Pages with high keyword densities ranked well, while low keyword density pages did not. Now imagine how long it took for people to figure this out. As soon as people got wise of this, they began intentionally stuffing tons of keywords and phrases into the bottom of their websites to raise their keyword density. Search engines became wise of this and began taking measures to prevent manipulated results from reaching the top positions.
Search engines have been improving indexing algorithms for years thus making keyword density a much less important factor in ranking your web page. Is keyword density still important? Yes. I say that without a doubt. A page with a strong keyword density sends a clear message to search engines, “this keyword is without is absolutely the keyword I want to rank well for”. Define your keywords in your meta and description and you couldn't target your keyword any better with a laser.
So here's the low down on how to use keyword density efficiency. It's pretty obvious but I'll mention it anyways. Stick to one keyword or key phrase per page. You don't want to be ranking for ice picks and bicycles on the same page. That's pretty easy to understand right?
Keep your keyword density below 12%. Anything higher than that will look like you intentionally stuffed your page to rank better. I try to stick to about 10%. Also, avoid stuffing keywords into your page. I said avoid because sometimes it's necessary to stuff your page but it should be considered only as a last resort and you'd better do it right because search engines are smart and can pick this amateur attempt out pretty quick. Remember, the key is to do it right.