Search Engine Optimization, or SEO, is the art of taking a website and pushing it up the ranks of the major search engines. SEO first emerged in the late 90s as powerful search engines such as Google were coming to the forefront. Web masters soon realized that in order to succeed online they needed to work to have their websites in the top ranks of search results.

Promoting or "optimizing" a website was at first a simple and direct matter, involving only a few well known factors. The first generation of search engines relied on what are known as metatags to categorize the content of a web page. A metatag, however, did not have to relate in any way to a website's content. This soon resulted in search results that had nothing to do with what the user was looking for. This was a result of both bad design and abuse of the system.

Efforts were soon made to counteract the abuse of metatags. Successful search engines moved away from using the metatag, and began to rely on a combination of links and keywords in a page's HTML. Although this improved the accuracy of search results, it still provided an avenue for abuse. Some web masters began to "stuff" their websites with unrelated keywords. The selling and trading of links also became a widespread phenomenon.

The algorithms of the latest generation of search engines are a well kept secret. It is known, however, that search engines like Google rely on complicated algorithms that calculate the likelihood that a surfer would randomly come across a website. This algorithm is a function of link strength and quantity.

Although SEO can draw traffic to a website, it should not be relied upon as the sole means of supporting a website. Once SEO improvements are made, a page's rank should indeed rise, but search engines often change their algorithms. A page relying completely on search engine results may suddenly lose a significant portion of its traffic if a popular search engine should change its algorithm. A better foundation for a website relies upon both search engine results and the strength of its connections to other websites.

Modern search engine optimization often relies upon not only targeting specific search engines, but also upon strengthening the overall presentational foundation of the website. As such, the line between SEO and web design is often blurred. Many web designers consider SEO as a part of their services. SEO experts are sometimes brought in when a website is already built, but isn't drawing the traffic. This can be due in part to problems with the indexing of pages. An SEO expert first ensures that the search engines can properly index, or spider, a website.

SEO is an important service for many websites, but it is not a magic bullet.