But not everyone seems to grasp the fact that it's an ever-changing field of marketing. As search evolves so do the complex algorithms the search engines use to determine which sites are relevant to which search terms.
Why the constant changes?
That's mainly down to the less than white SEO 'experts' out there who find a technique to boost their website's rankings and exploit it.
For example, as a result of websites with poor content that wasn't relevant, Google's Panda came along. Hot on its heels was the mighty Penguin to battle against keyword stuffers, cloaking, duplicate content and those participating in link schemes.