Search engine optimization
Every search engine has its own algorithm that determines the ranking of documents within search results. A search engine algorithm is a complex set of computer-based rules for how to interpret and rank web pages when users do a search for a particular word or phrase. For obvious reasons, search engines do not publicly reveal the detailed logic behind such algorithms.

There are lots of similarities in the way search engine algorithms work. To learn more about how search engines work or how to improve your rankings, visit Search Engine Watch to find information on search engines and their rules.

The three most important elements of search engine optimization are:

· Links and navigation
· Text and META-data
· Popularity measurement Keep your website online With the billions of web pages search engines have to visit each month they usually only have time to request each web page once. If your web server is not accessible at the time the search engines visit your website, your web pages won't get indexed. Don't panic!

Most search engines crawl the web on a regular basis. If some of your web pages have been dropped because your server was down, they will probably get back into the index the next time the search engine visits your website.

TIP:
There are several online services and software packages that can monitor your website and report any downtime. You can find a list of monitoring tools in the Lycos Open Directory.

Introduction to search engine spiders
Search engines use small computer programs to browse through and read web pages on the Internet. Such programs are often referred to as "search engine spiders" or "search engine robots". When a search engine spider visits a page it first reads the text on the page and then tries to follow links from that page off to other web pages and websites.

You can think of a search engine spider as a very simple form of automated browser. It traverses the Internet like a human would do with a browser - just many times faster and fully automated.

Unlike ordinary browsers, search engine spiders do not "view" web pages - they simply "read" the content and click the links. Search engine spiders do not enjoy or appreciate the great design and "cool" images on your web pages.

Validate HTML
HTML code is the most fundamental part of every web page on the Internet. In a browser, you don't see the actual HTML code, but only the final result - the web page as it should look.

Search engine spiders, however, can't see the web site's final result, and instead, focus on the raw HTML code.

Most browsers can interpret HTML code that has errors and still show a nice looking page. However, you never know how a search engine spider will interpret the same errors. It may skip the part that uses incorrect syntax, or it may skip the entire page or website. There is no way to predict what the search engine spider will do when it encounters code it doesn't understand.

If search engines cannot decode your website, follow the links, and read the text, your site will not get indexed. It is not enough to validate your web pages by looking at them in your browser. The HTML syntax needs to be correct - you need to validate your HTML.

TIP:
Some editors have built-in HTML validators. Use them! If you are using Search Engine Submission, you will have access to the built-in HTML syntax checker. The syntax checker is a simple version of a full HTML-validator and will serve as a useful tool to find and correct errors in your HTML code.

If you do not have access to any of these validators, we strongly recommend using the free HTML validator or one of the many validators you can find in the Lycos Open directory.

Stay away from "alternative HTML"
Some search engine optimization "experts" will advise you to use non-standard HTML to squeeze in extra keywords in hidden places in your HTML code. Do not do that! Search engines penalize websites that use hidden keywords either by de-ranking the websites or erasing them completely from their index. Always use valid HTML.