What is SEO?
When you type a word into a search engine, you'll receive a list of websites that are associated with that word. If you're like most users, you click on the results that are higher up in the list and don't pay much attention to those further down the page. Why do these pages rank higher than the others? It's because of SEO, or search engine optimization. This is a powerful tool that can be used by web marketers to get their company in front of potential customers.
SEO helps search engines to find and rank sites according to the search word. The better your SEO ranking, the higher your page will appear and the more visitors you'll get.
Read on to find out more about search engine optimization, including how it works and how the major search engines rank websites.
1. How Search Engines Work
Something to keep in mind: SEOs aren't people. How your search engine finds results and how a human would find results are very different. Search engines are test driven, meaning they ignore beautiful web design and splashy graphics. They crawl the web reading text to figure out what the site is about. This includes indexing, calculating for relevancy, information processing, and retrieval.
A crawler or a spider (or in Google's case, a Googlebot) will search the web to find appropriate sites for each query. Spiders will actually go through the page through its links to index its contents. Since there are over 20 billion pages currently online, obviously the crawlers can't visit every site daily to check for new information or modifications. It may take a month or two for it to review your page.
The easiest way to make sure a crawler will see your site, check your content to make sure the text contains information that helps it to stand out. It won't see images, JavaScript, frames, images, or pages and directories with password protection. If there a lot of these items on your site, run this Spider Simulator to see if a spider is likely to see your content. If not, they can't be indexed, processed, etc. Search engines won't even know they exist.
The crawler will then index the content of your page in a huge database for retrieval. This involves identifying the keywords that help to identify your page as a valid search result when a certain term is searched. Although the search engine may not always completely understand what your site is about, will help it classify your page and allow it to receive higher rankings.
When a search request is received by a search engine, it compares the search to the indexed pages collected in its database. Thousands, if not millions, of pages will contain that search string, so the search engine must rank each site according to its relevance.
Relevancy is calculated using different algorithms, each using weights depending on factors such as links, metatags, and keyword density. Since each search engine uses different algorithms, you'll find that searching the same keywords can return different results through the various services. Google, Yahoo!, Bing, and other major search engines also change their algorithms, so your pages will need to be adapted to meet the new requirements for your site to get to the stop and stay there. This is just one reason to use professional SEO services.
There are various algorithms to calculate relevancy. Each of these algorithms has different relative weights for common factors like keyword density, links, or metatags. That is why different search engines give different search results pages for the same search string. What is more, it is a known fact that all major search engines, like Yahoo!, Google, Bing, etc. periodically change their algorithms and if you want to keep at the top, you also need to adapt your pages to the latest changes. This is one reason (the other is your competitors) to devote permanent efforts to SEO, if you'd like to be at the top.
Finally, the search engine retrieves the results and displays them on your browser, starting with the most relevant site on the top of the first page.
2. How the Major Search Engines Differ
The major search engines are basically the same as far as principles of operation; however, their minor differences can cause major differences in relevancy of results. A common joke when Bing was introduced was that the algorithms were written to be completely opposite of those used by Google. Although this may be true, search engines focus on different site attributes. If you want your website to rank at the top of all of them, you'll need to optimize your site.
What are some of the most notable differences? Bing and Yahoo! focus on keywords, while Google is more dependent on links. Google also concentrates on sites that are older, while Yahoo! Doesn't seem to care about a site's age. This may mean that your site will take longer to reach the top of Google than it will on Yahoo!
