What are search engines?
Most of us know the answer to this and have used one at some point. Typically Search Engines are websites that help people search the web or a specific website, but not all search engines are the same.

Search engines come in two flavors, crawler-based and directories. These two types of search engines gather their listings in very different ways.

Human-Powered Directories
A human-powered directory, such as Yahoo, depends on humans for its listings. Your site is reviewed by an editor and if deemed worthy, they add it to directory. You can submit your site to directories. It is important to provide an accurate description of your site in these submissions.

Changing your web pages has no effect on your listing. Things that are useful for improving a listing with a search engine have nothing to do with improving a listing in a directory. The only exception is that a good site, with good content, might be more likely to get reviewed for free than a poor site.

Crawler-Based Search Engines
Crawler-based search engines, such as Google, create their listings automatically. They "crawl" or "spider" the web and then store the information it finds in an "index" (also called a catalog) that are used to provide search results for the search engine users.

If you change your web pages, crawler-based search engines will find these changes, and that can affect how you are listed. The more often your pages change, the more often your site is spidered. This is why keeping your content fresh is so important. Page titles, body copy and other elements all play a role.

A question on everyone's mind is how to improve their google ranking. Google is really a popularity contest. While there are multiple factors to consider, essentially the more sites that link to yours, the higher your rank will be.