Duplicate content is a mistake that can often be very difficult to know you have made. You publish a piece of content on your website yet somehow it is being flagged as duplicate content on your website? Has Google made a mistake or is there something wrong?
More often than not, Google has not made a mistake and you may not have necessarily made a mistake either. If this happens to all of your blog posts then you more than likely have a server issue that could require some more advanced web development knowledge to resolve. If it is just a single report of a duplicate page, then maybe the error is genuine. It is always worth double checking there are not multiple pages with the same content that somehow got published by accident.
How To Fix Duplicate Content Issues?
This is fairly easy to fix, assuming you have not copied content from another website. If you straight up copy content on a site that you do not own, it can get you into some legal trouble. Delete the content right away and make sure you never do this again. If you have copied the content from your own website, then there are a few ways to go about it.
To fix a regular duplicate content issue, you first need to delete the duplicate content. Pick the post you want to keep and delete the one you do not. Update any internal links to the old post or setup a 301 redirect so that any old internal or external backlinks to the deleted page, redirect to the correct page. In some cases, if you want the post to appear in menus to benefit the user experience, keeping the post on the site is fine, so long as you use a 301 redirect.
What if content needs to be published multiple times?
This happens from time to time and there is a solution for this. If you need to publish the same thing on multiple areas of your website, you need to decide which is the primary version. If anyone has ever used AMP or has a mobile version of their site, you should be familiar with canonical URLs. A tag is placed in the head of the HTML that tells Google that this is not a unique page and rather than index this page, index the URL provided in the Canonical tag.
<link rel="canonical" href="http://www.example.com/the-version-you-want-google-to-index/" />
By using the tag above on any duplicate page, you will avoid getting a content penalty for having similar content on your website. Deciding which version should be considered the original content is entirely up to you, but you must provide this tag to avoid the penalty if you are publishing the same thing on separate pages.
What’s the difference between Canonical and a 301 redirect?
In terms of search engine rankings, both of these should yield the same results. Both will tell Google to go to a different page to index the content, the posts differ when it comes to the end user experience. If a user visits a duplicate page with a 301 redirect, the browser will bring them to the original post. If there is a canonical link, it will still let them view the duplicate page.
A Duplicate Content Penalty is not Permanent
At the end of the day, there is nothing wrong with duplicate content on a website, so long as you declare it. The Google duplicate content penalty is not a punishment as such. From their perspective, they have found the same thing twice and do not know which to index. They cant index both, so they index nothing and wait for you to fix the problem.