How Search Engines Work
Search Engines vs. Directories
There is a difference between a search engine and a directory. A search engine is a machine - or a "robot." A human may program algorithms for a search engine, but a human will have nothing to do with your site when the spider is visiting your site or the engine is indexing your pages.
A directory can be compiled by a robot, but more often than not, it is compiled by humans. Dmoz is a good example of a directory. When you submit your site to Dmoz a human will review your site for consideration in their index.
Each major "search engine" is usually associated with a "directory." For instance, Google and Dmoz are a search engine and a directory, respectively. They are two separate entities. However, Google uses results from the Dmoz directory. Therefore, if you do a search in Google, pages that are also listed in the Dmoz directory may come up with a higher rank than pages that are not listed in the Dmoz directory.
If you want to get good ranks in search engines, it is imperative that you are listed in the directory associated with each search engine.
You can see the relationships between all the engines and directories on Bruce Clay's Search Engine Relationship Chart. Notice the strength of the Dmoz directory!
What happens when I submit my site to a search engine?
First, the search engine's spider will visit your site immediately, and schedule your site for inclusion in the search engine's index.
Second, usually within a few weeks, the engine will place your site in their index.
Third, the spider will revisit your site, to include any updates. Once you are included in the index, the spider will usually revisit every two weeks. The spider will also begin to "crawl" your site by following the links off of the page that you submitted.
Fourth, when someone uses a search engine, they type "keywords" into the search box. They are submitting a query to a search engine. The search engine, depending on how it has been tuned, will pull up all of the relevant sites which pertain to that query.
What if I don't want a page indexed?
If you want to prevent a search engine from indexing certain pages insert a <meta name="robots" content="noindex"> tag in the head section of every page that you don't want search engines to index.
Better yet, you can very simply include a robots.txt file in your main directory - in this way you can exclude all engines from certain parts of your site, or specific engines from specific pages. Directions on how to do this are located at: Robots Exclusion Standard
Variables That Affect Ranks
- Focused, well-written content
- Link popularity
- Keywords in the title tag
- Keywords in heading tags <H1> to <H6>
- Keywords in the body copy
- Keywords in the names of the linked pages (both in the link name and in the link text
for instance: <a href="educational-toys.htm">educational toys</a> - Keywords as names of images and in alt tags
for instance: <img src="edcuational-toys.gif" alt="educational toys"> - Keywords in the description tag
Introduction to Search Engine Optimization | Link Popularity| How To Submit
