Duplicate content occurs when two websites display identical or very similar content on any number of pages.
This can happen when one website copies the content of a competitor or even when webmasters host the same content across a range of different domains.
Search engines penalise websites with duplicate content, as they don’t want the same information appearing more than once in any search query.
Nobody can be certain of the exact penalties that are applied (which can be as harsh as removal from the search index) but one thing is for sure, they will harm your rankings and traffic.
According to the Google webmaster blog, Google first looks to filter out pages with duplicate content and list only the first version, and only penalizes sites if they perceive a deliberate attempt to manipulate rankings.
The Google webmaster blog shares a range of ways webmasters can proactively address duplicate content issues, some of which Dr Search highlights below:
Block appropriately: Rather than letting search engines determine the “best” version of a document, you may wish to guide them to your preferred version. For instance, if you don’t want them to index the print friendly versions of your site’s articles, disallow those directories in your robots.txt file.
Use 301s: If you have restructured your site, use 301 redirects to smartly redirect users and search engine spiders.
Be consistent: Endeavour to keep your internal linking consistent; for example always link to your homepage using example.com instead of example.com/index.html
Syndicate carefully: If you syndicate your content on other sites, make sure they include a link back to the original article on each syndicated article.
Use the preferred domain feature of Google webmaster tools: If other sites link to yours using both the www and non-www version of your URLs, let Google know which way you prefer your site to be listed using the preferred domain feature.
As a final word, don’t worry too much about sites that republish your content without permission, as it’s highly unlikely that these sites can negatively impact your ranking.
Take notice of these Google tips and you can be confident knowing you’ve taken a proactive approach to avoiding duplicate content issues.