Search Engine Robots - How They Work, What They Do (Part I)

Automated search engine robots, sometimes called "spiders" or "crawlers", are the seekers of web pages. How do they work? What is it they really do? Why are they important?

You'd think with all the fuss about indexing web pages to add to search engine databases, that robots would be great and powerful beings. Wrong. Search engine robots have only basic functionality like that of early browsers in terms of what they can understand in a web page. Like early browsers, robots just can't do certain things. Robots don't understand frames, Flash movies, images or JavaScript. They can't enter password protected areas and they can't click all those buttons you have on your website. They can be stopped cold while indexing a dynamically generated URL and slowed to a stop with JavaScript navigation. How Do Search Engine Robots Work?

Think of search engine robots as automated data retrieval programs, traveling the web to find information and links.

When you submit a web page to a search engine at the "Submit a URL" page, the new URL is added to the robot's queue of websites to visit on its next foray out onto the web. Even if you don't directly submit a page, many robots will find your site because of links from other sites that point back to yours. This is one of the reasons why it is important to build your link popularity and to get links from other topical sites back to yours.

When arriving at your website, the automated robots first check to see if you have a robots.txt file. This file is used to tell robots which areas of your site are off-limits to them. Typically these may be directories containing only binaries or other files the robot doesn't need to concern itself with.

Robots collect links from each page they visit, and later follow those links through to other pages. In this way, they essentially follow the links from one page to another. The entire World Wide Web is made up of links, the original idea being that you could follow links from one place to another. This is how robots get around.

The "smarts" about indexing pages online comes from the search engine engineers, who devise the methods used to evaluate the information the search engine robots retrieve. When introduced into the search engine database, the information is available for searchers querying the search engine. When a search engine user enters their query into the search engine, there are a number of quick calculations done to make sure that the search engine presents just the right set of results to give their visitor the most relevant response to their query.

You can see which pages on your site the search engine robots have visited by looking at your server logs or the results from your log statistics program. Identifying the robots will show you when they visited your website, which pages they visited and how often they visit. Some robots are readily identifiable by their user agent names, like Google's "Googlebot"; others are bit more obscure, like Inktomi's "Slurp". Still other robots may be listed in your logs that you cannot readily identify; some of them may even appear to be human-powered browsers.

Along with identifying individual robots and counting the number of their visits, the statistics can also show you aggressive bandwidth-grabbing robots or robots you may not want visiting your website. In the resources section of the end of this article, you will find sites that list names and IP addresses of search engine robots to help you identify them. How Do They Read The Pages On Your Website?

When the search engine robot visits your page, it looks at the visible text on the page, the content of the various tags in your page's source code (title tag, meta tags, etc.), and the hyperlinks on your page. From the words and the links that the robot finds, the search engine decides what your page is about. There are many factors used to figure out what "matters" and each search engine has its own algorithm in order to evaluate and process the information. Depending on how the robot is set up through the search engine, the information is indexed and then delivered to the search engine's database.

The information delivered to the databases then becomes part of the search engine and directory ranking process. When the search engine visitor submits their query, the search engine digs through its database to give the final listing that is displayed on the results page.

The search engine databases update at varying times. Once you are in the search engine databases, the robots keep visiting you periodically, to pick up any changes to your pages, and to make sure they have the latest info. The number of times you are visited depends on how the search engine sets up its visits, which can vary per search engine.

Sometimes visiting robots are unable to access the website they are visiting. If your site is down, or you are experiencing huge amounts of traffic, the robot may not be able to access your site. When this happens, the website may not be re-indexed, depending on the frequency of the robot visits to your website. In most cases, robots that cannot access your pages will try again later, hoping that your site will be accessible then.

Resources

*SpiderSpotting - Search Engine Watch http://searchenginewatch.com/webmasters/spiders.html

*Robotstxt.org List of robots and protocols for setting up a robots.txt file. http://www.robotstxt.org/

*Spider-Food Tutorials, forums and articles about Search Engine spiders and Search Engine Marketing. http://spider-food.net/

*Spiderhunter.com Articles and resources about tracking Search Engine spiders. http://www.spiderhunter.com/

*Sim Spider Search Engine Robot Simulator Search Engine World has a spider that simulates what the Search Engine robots read from your website. http://www.searchengineworld.com/cgi-bin/sim_spider.cgi

Daria Goetsch is the founder and Search Engine Marketing Consultant for Search Innovation Marketing, a Search Engine Optimization company serving small businesses. She has specialized in Search Engine Promotion since 1998, including three years as the Search Engine Specialist for O'Reilly Media, Inc., a technical book publishing company.

Copyright © 2002-2005 Search Innovation Marketing. http://www.searchinnovation.com All Rights Reserved.

Permission to reprint this article is granted if the article is reproduced in its entirety, without editing, including the bio information. Please include a hyperlink to http://www.searchinnovation.com when using this article in newsletters or online.

In The News:


pen paper and inkwell


cat break through


If You Could Submit Just One Page To The Search Engines Which Should It Be?

Listen. Some make submitting pages to search engines sound like... Read More

Hiring An SEO Constultant - 10 Reasons Why You Should

It crosses every webmaster's mind anytime they see an ad... Read More

How To Boost Your Keyword Density On Your Web Site To Gain Top Positions At The Search Engines

Let's talk about what keyword density is and how to... Read More

Google Sitemaps Explained - How To Use Google Sitemaps

Three Ways To Index Your Site With Google Sitemaps [Difficult,... Read More

Anchor Text Optimization

Anchor Text (also called phrase linking) can significantly improve your... Read More

How To Start An Internet Business ? Meta Tags and Keyword Density

Okay, you have a domain name, layout and content. Now... Read More

Absolute & Relative Links How Do They Rank?

The question for this article is whether or not you... Read More

How to Google; or How to be Easily Distracted

I set out with the intention of writing a self... Read More

The Secret Benefit Of Search Engine Optimisation: Increased Usability

A higher search ranking is what many website owners dream... Read More

Five and a Half Ways to Amp Up Your Search Engine Optimization

Statistics show that 85% of pages visited on the Internet... Read More

The Search Engine Optimization Secret that Everybody Ignores

Search engine optimization is a very critical task in the... Read More

Why You Should NOT Submit Your Site On Search Engines

Before to answer to this question we have to know... Read More

Site-Digest 7 Simple Steps To Place Your Site Map On Steroids

The Site Map is a too often overlooked piece of... Read More

Valid HTML code is crucial to Search Engine Optimization

Why valid HTML code is crucial to your web site's... Read More

Search Engine Optimization: Site Structure and Popularity

In the Global Internet era the industry presence is undoubtedly... Read More

Local Customers Know Where to Find Local Businesses... the Internet

Through search engines and directories, the Internet provides a quick... Read More

Link Popularity Pitfalls

As we all know Google uses their PageRank technology to... Read More

Find Best Keywords For Your Site

Keyword optimisation is probably the most important thing that you... Read More

Maximize Your Search Engine Traffic - 13 Ways to Pull in More Visitors From the Search Engines

Maximizing traffic from the search engines to your web site... Read More

How Important is PageRank, Really?

Webmasters can spend most of their waking hours doing everything... Read More

Diary of a Google Gazumpee

Back in November, when the Google Dance began, Barry Lloyd... Read More

Search Engines: Different Types, Different Strategies

There are four basic types of Search Engines: Free Search... Read More

Getting Listed in the ODP, Google Directory

First of all, the Google directory is really just the... Read More

The Easiest Way to Your Google Sitemap

Google Sitemaps is a new tool for website owners and... Read More

A Naive Mistake Cost Me My Google Rankings

Little do you know but you too could be making... Read More

SEO Training - Avoid Making this Costly Mistake!

SEO training can be overwhelming. There are literally hundreds of... Read More

How To Make Your Website More Successful? (Part II)

In part I of our series of how to make... Read More

Free Search Engine Advertising: 10 Secret Ways To Indirectly Race To The Top Of Search Engines

Do you have a website that has little or no... Read More

Marketing Articles: Getting A Better Search Engine Rank For All Of Your Pages!

In one of my articles, I discussed how to market... Read More

The Matrix Help For Keyphrase Analysis

Keyword analysis is a major part of search engine marketing.... Read More

Link Exchange Tips, No Tricks

Use text links, avoid image links. Anyhow, if you... Read More

Common Sense Approach to Search Engine Optimization

Most web surfers start their sessions at a search engine... Read More

Sitemaps 101 - Back to SEO School

Sitemaps are without doubt one of the most often ignored... Read More