Overview

When users type a keyword or phrase into a search engine query box, they receive a listing of websites that presumably offer information, products or services related to that keyword. Search engines strive to list the most qualified websites at the top of the list. Search Engine Optimization (SEO) is the practice of modifying visible and invisible website content in addition to establishing links from other relevant websites. The purpose is to gain higher ranking among search engines.

Developing an SEO campaign starts with a basic understanding of how search engines work. Search engines are different and fall into two distinct categories: spider-based and directory-based. Each has unique ranking methods requiring different website optimization strategies.

Directory-Based Search Engines

Directory-based search engines are more of a directory listing, similar to the "Yellow Pages". Listings are classified into groups so users can navigate through layered categories. However, many users search by keyword or phrase (e.g. dog food). When a user enters a search phrase, the directory searches for word matches in the listed title, description and URL, and, in some cases category name. If a website listing includes either the term "dog" or "food", the website may be included among the search results. If none of these terms are uses in the listed text (e.g. canine chow), then the website may not be included among the results.

Assuming the site is listed among the results, it may be ranked near the top where many visitors can find the listing and click to the site. Or it may be ranked poorly where only a few visitors will find the site listing. The higher the ranking, the better the chances that visitors will click to the site.

While directory-based SEO campaigns optimize websites by strategically including keywords in the site listings, there are other attributes that affect ranking. To some degree, ranking is established by website popularity: how many visitors go to a site and how long they stay there. Sites with higher popularity receive higher ranking.

It is very important that a new site be properly optimized; otherwise its listing will not receive reasonable exposure. Without this exposure, popularity will not increase.

Without exception, directory-based search engines employ editors to review each and every submitted listing. These editors inspect the website to make sure the site is in good working condition and the submission listing properly represents the website content. Yahoo offers fee-based express services for businesses (non-profit organizations are free). However, as of February 2004, their primary search tool has been changed to their own spider-based seaerch engine. On the other hand, ODP (Open Directory Project) employs volunteer editors. All listings with ODP are free, but listing delays are common.

Spider-Based Search Engines

Spider-based search engines look and behave like directory-based search engines, but spider-based search engines use a significantly different way to rank websites.

As the name implies, these search engines use "spiders" to crawl through a website and examine visible and invisible content, and the strength of its link structure. Each search engine uses unique and confidential algorithms to rank websites.

Spider-based search engines employ complex mathematical algorithms in an attempt to assess a website's content focus by reading visible and invisible text (including link structures). The more focused the site content, the higher the ranking when a search engine user types specific keywords or phrases into a search box.

A page optimization campaign focuses on refining the visible and invisible content of a website, which allows the search engine to properly determine the site's keywords. Page optimization includes modifying existing pages and/or adding new pages with optimal keyword densities and proximity. But spiders cannot read the content of all websites.

Websites with frames or dynamic page construction are not search engine-friendly. Many search engines cannot read content within frames or pages created dynamically. Google and Inktomi claim to follow frame sets; Google and Yahoo can read some level of URLs with "?" in them. In some cases, site construction must be changed or an alternative strategy employed.

Websites with graphic intensive pages that do not have content or text links (common on some home pages) should be modified to include these elements or an alternative strategy considered.

Occasionally, website managers will not permit visible text enhancements to their site. If the visible content cannot be enhanced with keywords, the optimization effort may be compromised, resulting in poor ranking.

A link optimization campaign builds a strong link structure by increasing the number of inbound links from websites within in a similar category. A well crafted link from a relevant site is valuable in the eyes of the search engine, which closely inspects links to determine rank. However, some inbound links can be detrimental to a site's ranking. There is new evidence from the search engines that suggest, "free links", "link farms" or "link pools" may be harmful to a site ranking.

Fees for spider-based SEO campaigns vary significantly depending on 5 basic variables.

1. Number of keywords (more keywords: higher price)

2. Popularity of keywords (more popularity or competitiveness: fewer number of keywords and/or higher price)

3. Number of high quality links to attain from other websites within the same or similar category.

4. PageRank - A crucial factor in Gogle's ranking algorithm is the measure of how interconnected a website page is to all other pages.

5. Implementation strategy influenced by website design, client constraints and page optimization strategy (e.g. site content optimization, doorway page, cloaking)

The Search Engine environment is constantly changing. Spider-based search engines are continually refining their search algorithms with several new releases each year, and more websites are competing for top ranked positions. To maintain top ranking, SEO campaigns must constantly report, refine and improve optimizing tactics.

Conclusion

The SEO business has dramatically changed since mid 2000. What once was a relatively easy task of optimizing web pages for top ranking among the most popular search engines has turned out to be a complex process requiring research, analysis, and skill.

Spider-based optimization is a complex process that involves many variables. As the popularity and/or number of keyword phrases increases, the number of HTML/text pages must also increase to produce a theme strength that will compete favorably with the existing top-ranked websites. Also, by analyzing the strength of the link structure of top ranked websites for the same keywords, the level of link optimization can be defined. Optimization for Google rankings requires an assessment of the site's current PageRank and the competing PageRank for each search term to determine if an increase is necessary.

The following table summarizes the fundamental attributes of each search engine type and cost impact.