What is the 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 humans have nothing to do with your site when the spider is visiting your site or when the engine is ranking your pages. Google.com is an example of a search engine.

For the most part, humans compile directories. Dmoz.org (Open Directory Project) is an example of a directory. When you submit your site to Dmoz, a human will review your site for consideration in the Dmoz directory of web sites.

A search engine has a very large database because it will store several pages of every web site it indexes. A directory will only store a link to the home page of each site and a description.

Search engines will take the description either from some of the sentences on the web page or from the description meta tag. A directory will take the description from your submission information. Each major search engine is usually associated with a directory. For instance, when you go to Google and you type in a search, you are getting results from all the web sites stored in Google's database.

It is believed that Google's algorithms are also programmed to place emphasis on sites that are also listed in the Dmoz directory. However many top SEO’s argue this holds less weight today.

It is a good idea to get listed in as many directories as possible. This simple piece of software can save you a lot of time and effort: Directory Inclusion.

About Search Engine

What is a Search Engine?

Search engines are the primary tools of Internet users for finding products, services and information

over the web. Search engines allow people to search the entire Web (or at least those pages of the

Internet that are in the search engine's database.)

How Does a Search Engine Index Web Pages?

There are four parts to an engine that you need to know about for optimization purposes:

•  The spider is a program that  goes out across the internet,  looks for and gathers up web

pages.

•  The database is where the spider will store the pages that it finds.

•  The search engine website, e.g. google.com,  is where searchers go to pull up information

from the database.

•  The algorithms are programs that determine which sites will come up when searchers type in

a query at the search engine website.

There are two ways that your site can get into the database:

•  The spider will automatically find your site from a link on someone else's site which is the

path we recommend if you can get 1 or more quality inbound link(s).

•   You submit your URL so that the spider will come out and find it.

What Happens When I Submit my URL to a Search Engine?

First, the search engine's spider visits your URL immediately and schedules your page for inclusion in

the search engine's database.

Second, usually within a few weeks, the spider comes along and places your page(s) into its database.

There is no telling how many pages deep the spider will crawl or how many pages it will place in the

database. Usually, on the first time around, it will be only a few pages -possibly only the home page.

Third, the spider revisits your page(s) to grab any changes you've made. (The old term for this was

"automatic update.") Once a page is in the database, the spider usually revisits every few weeks. The

spider will also begin to crawl your site more deeply and place more and more of your pages into the

database.