How Search Engine Crawlers Work

A search engine crawler is a website's best friend in terms of search rankings. Hopefully, a clearer understanding of what they are and how they work can help your website attain higher rankings.

Also known as a spider, robot, bot, ant, worm and some other names, a crawler is software that scans the World Wide Web in a systematic and automated way. Web crawling or spidering is done mainly for gathering information to be later indexed in central directories. Crawling can also be used for website maintenance tasks such as validating HTML code or checking links.

The main function of a search provider is to search for information on the web and in available databases and open directories. It operates by web crawling, indexing and searching by using one or more spiders. It gathers information about web pages from the HTML themselves and every link on the site that the spider finds. Most spiders recognize only text but some crawlers do recognize images with special HTML code.

Different search providers have different ways of indexing or storing data. Some search providers index all or just a part of the searched web page after analyzing the relevance of information they want to store. Other search companies, on the other hand, index every word of every page their crawlers find. Another difference in the indexing system is that some search companies use a predefined and categorized listing of keywords determined by humans while other search engines rely more heavily on the machine itself and automation.

Moreover, even if two search providers use their keyword indices as the basis for ranking the same website, the relevancy of each other's keywords may still differ. As a result, that website may attain two different rankings from each search engine. Due to these differences in indexing methods, page rankings of one website widely vary from one search engine to another. Search engine results page ranking, therefore, is not absolute and it should not be the sole factor to be considered in achieving effective SEO.

Search operation has proven to be a profitable commercial venture. With the emergence of thousands of search providers, millions of spiders roam around the ever-expanding World Wide Web. As the spiders flood websites and servers, traffic jams do happen in the affected sites, and glitches and snags sometimes interrupt their operation.

Search engine crawlers are an indispensable part of search engines. Befriending them with quality and relevant content in your website makes good business sense for higher search engine results page ranking.