Search Engine Optimization, as defined by Wikipedia, is “the process of improving the volume and quality of traffic to a web site from search engines via “natural” (”organic” or “algorithmic”) search results for targeted keywords.” (Wiki 1). This is accomplished by optimizing your website to best take advantage of the weighting factors (namely the content on a page, as well as the quality and number of links pointing to this page) search engines use to determine the order of the pages they will index.
How SEO works
If your website sells blue widgets, ranking 1st for the phrase “blue widgets” would be advantageous for you, since people searching for “blue widgets” will come across your site, and the higher you rank, the more clicks you’ll receive, and the more blue widgets you will sell. The same principle holds true whether your business model is retail (such as the above hypothetical situation), informational, B2B, etc.
Search engines are in the business of being used for search purposes, and it’s their job to return the most relevant results to their users. After all, if a competing search engine begins offering superior (as in, more useful) search results, users will begin gravitating towards this other search engine, and this loss of traffic will affect their revenue sources (such as displaying ads, where revenue depends largely on visits).
Keeping this in mind, it’s clearly in their best interest to display the most relevant results for the user’s chosen keyword(s), as they are essentially telling their users that the resulting search results, are the most relevant pages for their chosen search. Theoretically speaking, good SEO means good user experience. For this reason, search engines factor in the number of times a key word or phrase appears on the page–ideally, the more times a page mentions the phrase, the more relevant that page is to the respective word or phrase. Likewise, the more pages that link to a specific page, the more important that page is deemed (since each links is seen as a vote). Furthermore, these votes are not all necessarily equal. The importance and relevance of these inbound links are also factored into this equation.
SEO mostly comprises of ensuring that your website is full of content relevant to the key words and phrases your ideal visitors will be typing, as well as having plenty of other websites linking to your website (ideally, websites with content also relevant to your keywords and phrases).
What SEO isn’t
SEO is not a collection of clever techniques. While specific changes and quick fixes can certainly help your SEO efforts, the most highly optimized sites use SEO as an approach, rather than an addition. Your code should be clean and light. While repeating your targeted keywords over and over may help, unintelligently adding these keywords to your pages will turn off users and defeat the purpose getting people site to your page to begin with. Effective SEO copy intelligently explains your product or service. Simply buying links will only get you so far and using link farms won’t help you at all (and may even hurt your SEO efforts). Having links from sites (especially established sites, with many inbound links themselves) relevant to your targeted keywords will pay off in spades. But such links generally must be earned through the display of useful and relevant content. Hence, by helping the visitor, you are essentially helping your own SEO effort. Effective SEO is a win/win/win concept, with the winners being your website, the user, and the search engine.