In the digital age, almost everyone has an online presence. Most people will look online before stepping foot in a store because everything is available online—even if it’s just information on where to get the best products. We even look up cinema times online!

As such, staying ahead of the competition regarding visibility is no longer merely a matter of having a good marketing strategy. Newspaper and magazine articles, television and radio advertising, and even billboards (for those who can afford them) are no longer enough, even though they’re still arguably necessary.

Now, you also have to ensure that your site is better than your competitors’, from layout to content, and beyond. If you don’t, you’ll slip away into obscurity, like a well-kept secret among the locals—which doesn’t bode well for any business.

This notion is where search engine optimization (SEO) comes in. There is a host of SEO tools and tricks available to help put you ahead and increase your search engine page ranking—your online visibility. These range from your use of keywords, backlinks, and imagery, to your layout and categorization (usability and customer experience). One of these tools is the website crawler.

What is a Website Crawler?

A website crawler is a software program used to scan sites, reading the content (and other information) so as to generate entries for the search engine index.  All search engines use website crawlers (also known as a spider or bot). They typically work on submissions made by site owners and “crawl” new or recently modified sites and pages, to update the search engine index.

The crawler earned its moniker based on the way it works: by crawling through each page one at a time, following internal links until the entire site has been read, as well as following backlinks to determine the full scope of a site’s content. Crawlers can also be set to read the entire site or only specific pages that are then selectively crawled and indexed. By doing so, the website crawler can update the search engine index on a regular basis.

Website crawlers don’t have free reign, however. The Standard for Robot Exclusion (SRE) dictates the so-called “rules of politeness” for crawlers. Because of these specifications, a crawler will source information from the respective server to discover which files it may and may not read, and which files it must exclude from its submission to the search engine index. Crawlers that abide by the SRE are also unable to bypass firewalls, a further implementation designed to protect site owner’s’ privacy rights.

Lastly, the SRE also requires that website crawlers use a specialized algorithm. This algorithm allows the crawler to create search strings of operators and keywords, in order built onto the database (search engine index) of websites and pages for future search results. The algorithm also stipulates that the crawler waits between successive server requests, to prevent it from negatively impact the site’s response time for real (human) users visiting the site.