If two different URLs refer to (almost) the same content, search engine robots consider them to be two separate pages with "double" or duplicate content. You could also call it plagiarism. And that is punished.
Causes of duplicate content
The causes are manifold. Double content can occur both within your own website and across different domains.
Within your own website
- Your website has been poorly constructed technically. A domain is always accessible via two different URLs: the http and the www version, and preferably also via the https version. Googlebot sees all these URLs pointing to the same content as separate pages and therefore as duplicate content. Poorly set-up webshops also often cause problems, because products can be reached via several URLs.
- Creating duplicate content to rank higher. Sometimes, a conscious choice is made to place the same content on multiple pages, with only a minor adjustment. Think of entrepreneurs who create different pages about 'websites Leuven', 'websites Steenokkerzeel', with only the place name being different. They do this in order to be found, but in time they will be punished for this because of the copied content.
Across different websites
- Articles or pages are taken verbatim from other websites.
- In web shops , it is a common problem to use the standard descriptions of products from the manufacturer.
Consequences of duplicate content
Naturally, this has consequences for your SEO. Duplicate content is detrimental to your position in Google because the bot does not know which page you want to show. If Google encounters duplicate content, only one page will be listed in the search results. This is normally the page with the most and best links.
Google always strives for unique content. So if the bot encounters many URLs with the same content, the bot will stop crawling more quickly. It is therefore possible that a number of important pages will not be crawled and thus displayed in the search results.
A final consequence is that you have to control the strength of your incoming links
loses. Suppose you have 2 URLs containing the same content. One of them has 4 links and the other 2. Then you actually miss the chance to have 1 URL with 6 internal links.
Detecting duplicate content
Do you want to check if there is duplicate content on your website? A first step is to consultGoogle Search Console, via 'html improvements'. Here you can discover whether there are any duplicate meta descriptions or title tags, which could indicate duplicate content on your website.
Duplicate content across domains can be checked by entering your pages at Copyscape. Copyscape then checks for possible duplicates of the entered page.
- Simply remove duplicate content. Does your old page have incoming links and visitor traffic? Then create a 301 redirect.
- Redirect from http and https to www.
- Use a canonical tag to let Google know what your preferred URL is.
- Tells via the robots.txt let you know which pages may or may not be crawled by search engine bots. If you have duplicate content on a page, block that page.
- Contact the host or webmaster of the website that copied your content without permission. No response? Then submit a removal request to Google.