Search engine optimization is the process of building a website in such a way as to create maximum visibility for search engine robots and spiders. Search engine robots and spiders "crawl" the Internet looking for new, unique and useful information to store or "index" into their data bases. This information is then used to return the most relevant information possible to search engine users. These, in large measure are potential customers looking for your business. What makes a website most valuable to a search engine, however, is not tricks or slight of hand, but good quality content. Without this, SEO is of little use. Having said that, there are a multitude of variables which must be considered and employed to achieve optimum search performance. These include the proper use of valid HTML code, text-to-code ratios, meta tags, keyword density, unique text and much, much more. Further, optimum performance based upon these variables play a crucial role when weighed against the formulas search engines use (called algorithms) to evaluate and rank a site's relevance. To make matters a bit more worthy of SEO consideration are the fluid and dynamic nature of these algorithms which change over time. Therefore, when choosing a company to develop your website, be sure that they are competent at planning, implementing and managing all aspects of SEO as well.