"Search Engine Optimization is the process of taking a page built by humans and making it easily consumable for both other humans and for search engine robots."
What is Search Engine Optimization (SEO)?
Following best practices related to search engine optimization will make it easier for search engines to crawl, index, and understand your content. These changes may seem small, but when combined with other optimization efforts, they can impact your site's user experience and performance in organic search results (those not listed in the paid search results section of a search).
How does a search engine work?
So how does a search engine decide what to pull up when people enter their search terms? Well, each search engine has it's own different algorithms, and the science of searching has come a long way in the past ten to fifteen years. Techniques that worked a few years ago no longer work in today's search environments.
Search engines operate by constantly crawling websites and cataloging selected information in massive databases to be easily pulled up when someone searches. This may explain why you may find results in a search that lead to pages that are no longer available on the Web when you try to click on them--they've been removed from the original site, but the search database hasn't yet been updated to match.
Why is SEO important?
Searching is a trendy means of navigating the Web, reaching billions of people worldwide. Studies show that people are most likely to pay the most attention to links higher up in the search results. Therefore being listed in the first few search results for a given term greatly increases your site's visibility and credibility. People also trust sites that show up higher in search more readily.
Since search engines attempt to return results relevant to the search query and place them in relative order of importance (according to how well they appear to match the search terms), SEO deals with impacting these two characteristics of a site's data: relevance and importance. The concept of relevance in the context of a Web search has gotten much more complex since the inception of search engines, with hundreds of factors currently impacting a site's relevance in today's search environment. The importance a search engine places on a site regarding a particular search is currently translated as how popular the site is, assuming the more people have visited the site's data, the more valuable it must be.
Neither of these concepts is determined manually but rather through mathematical algorithms that involve hundreds of components or ranking factors. Many popular search engines (Google, Yahoo!, Bing) offer documentation to help website editors develop content optimized for their searches.
Remember: Site visitors come first!
While SEO is important, you should remember that the number one priority for developing your website content is what's best for the site visitors. Yes, it would help if you considered the tips listed in this section to make your site perform better in searches, but not at the cost of reducing site performance for the people who visit your site.