After all these years, SEO is still a black box for many people who ought to understand it. Many companies hire an SEO firm to create and manage their SEO strategy, but without an understanding of the basics, your chances of getting good results from an SEO vendor are low. So even if this stuff makes your eyes glaze over, it’s in your best interest to understand the basics yourself.
For you visual learners, the good people at SearchEngineLand have published an updated and clever poster of SEO success factors that make the learning process less painful. I am a sucker for a well-conceived infographic.