Web Jargon Explained: Spiders (and their effect on search engine optimisation)

A Spider (also known as web crawlers, web bots, web scutters, ants, indexers, and worms) is a program or script that browses the web in a process called spidering or web crawling.

Spiders are mainly used by search engines, and their job is to collect and store a copy (a cache) of the website for indexing to provide the most relevant results quickly. It is also the spidering process that is responsible for gathering updated information and making it available in search engine results.

Crawlers can also be used by web developers and SEO experts for maintenance tasks including searching for errors on the website such as broken links and redirect issues, checking backlinks are still active, and reviewing the existing SEO tags. One of the bad things about spiders is that they are frequently used by spammers to gather information from websites such as email addresses.

Web design and user experience are extremely important for crawlers when visiting your site. A crawler has a list of URLs to visit called a crawl frontier, these are links that have been collected from other web pages or submitted to Google using the Search Console submit sitemap or inspect URL feature. The crawler visits each URL on the list looking for internal and external links to other pages and adds them to the list to visit later. Likewise, if your link structure is complicated or there are an excessive number of links on the page, the spider will simply leave the site without collecting the data. The URLs on the list are crawled at regular points to check for new information which is used for search engine optimisation rankings. Changes can also be submitted via Google Search Console if you want them to be picked up faster.

Many people will have noticed that updates made on websites do not appear in search engines immediately, this is due to the volume of information on the world wide web. As spiders copy the information from a page they are limited to the amount of information they are able to process, this means that by the time information is added into the search engine there may be lots of new content on the site, or pages that have been removed completely! Unfortunately there is nothing anyone can do about the speed information appears in the search engines and no matter how good the search engine promotion team are, the results won’t happen over night!

Also due to the amount of information and the speed it is being added, only a small section of pages on the internet are indexed. A study of search engines showed that surprisingly, no search engine indexes more than 16% of the information on the world wide web – this makes a search engine campaign all the more important to ensure your pages are included in those results! If you think of the last time you Googled something and the millions of results displayed, just imagine how many results are missing that are included in the unindexed 84%! These sites are in the deep or invisible web and are unindexed because the regular crawlers can’t find them!

To make sure your website doesn’t suffer the same fate, why not give us a call on 0333 320 8099 and find out how our SEO packages can help you make sure the spiders are happily crawling around your web home!