Search Engine Optimization (SEO): Purpose of a Search Engine

On this page, we'll examine the basics of search engine optimization by identifying the role of search engines. On other pages, we'll develop the major, pertinent concepts in considerably more detail.

I shall sometimes describe a search engine as if it is some sort of thinking beast. In fact, of course, the decisions made by a search engine are based upon the variables and values that have been programmed into its algorithm by a number of very smart, but fallible, human beings.

Function of a Search Engine

One of the most important concepts for a business owner to recognize is that search engines consider the web to be a huge collection of individual files (pages) rather than a group of websites. In our capacity as webmasters, we think of our sites as making up an integrated whole, and we want our users to consider our sites in that way as well. Consequently, we need to create the individual pages in a way that integrates each into a human perception of a complete site while simultaneously making certain that a search engine algorithm will understand the page as a single entity.

The role of a search engine is to deliver results that are as relevant as possible to the search engine's understanding of what the user wants to find when that users enters a specific word or combination of words into the search box. In order to perform that function, the search engine must be able to attach some meaning to the search term entered by the user. More important to those of us who want our pages to show up in the results is the other thing that the search engine must determine: the content (topic) of each page. Only in determining those two parts can a search engine offer a "best guess" regarding displaying a list of results prioritized upon relevance.

How Do Search Engines Work?

Search engines are simply services of businesses that have found a way to make money by helping people find what they want to find on the vast Internet.  Thus, they have a vested financial interest in providing better results than their competitors.  Consequently, the businesses that operate search engines are always trying to improve their results. 

That means the formulas (algorithms) that search engines use to determine results for a particular search are often changed--sometimes slightly, sometimes radically.  However, those algorithms are always trying to determine intent of the searcher and content of web pages.

The task of determining what a user wants to find would be easier if all users conducted searches in identical ways.  Google, the most frequently used search engine, reports that in any given month more than half of the queries are unique.  Thus, in a year there are billions of searches that are different from each other.

Similarly, the task of determining what a page is about would be greatly simplified if no webmaster tried to mislead search engines about real content.  The deliberate misleading of search engine robots is often referred to as "black hat" SEO.  Some webmasters, for example, employ methods that are designed to make robots report one kind of content when the page is actually about something either slightly or even entirely different. 

As new "black hat" methods are employed, the search engineers must revise the algorithm to catch and discount the false information.  This of course complicates the task of legitimate SEO for those of us who simply want to convey accurate information about our pages.

Determining Page Topic

To try to figure out what a page is about and also establish its credibility, search engine algorithms include a large number of variables.  It is widely reported, although not by Google, that the Google algorithm considers around 100 variables.  However most people agree that the most heavily weighted of those variables are these (not necessarily in this order):

• Robot readable content on the page
• Page title
• Number of links and the link text of the links pointing to the page from within the site
• Number of external links pointing to the page (from other sites)
• Linking text from those external sources
• Reputation of the sites (or pages) linking to the page (impacts credibility but not the actual identification of the topic)

I'll address each of these on other pages, which are linked above.

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