A crawler is a computer program that automatically searches documents and websites on the internet. They are primarily programmed to undertake repetitive actions such as scanning different types of information.
Information that Crawlers scan for include:
- Links on a page
- Broken links
- HTML code validation
By scanning these types of information, crawlers are able to build a list of words and phrases found on the web-page and assign them to categories. This in turn creates a database.
Search engines such as Google, Yahoo and Bing use crawlers to maintain their database, by indexing downloaded pages, so when users are searching queries, they can find the results faster and more efficiently. The work of crawlers also has an influence on search engine optimization.
Without web crawlers, users would not be able to tell if a website has new or fresh content, or if the website is relevant to their search query.
Some crawlers and bots currently scouring the internet include:
- Slurp Bot
- Alexa Crawler
- Facebook External Hit
In Data Defined, we help make the complex world of data more accessible by explaining some of the most complex aspects of the field.
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