While Allegra cracked down on duplicate content, Bourbon, the subsequent update in May 2005, continued the process. Even within the same domain, pages with similar content are devalued. This algorithm change affected a lot of websites which led to a massive stir in the webmaster community.
At the time of the rollout, a Google spokesperson advised that webmasters should take a break from checking their sites’ rankings. The reason for this was that the team was conducting “3.5 improvements in search quality” which took a few days to complete. Bourbon was a continuation of the search engine’s focus on improving the relevance of search results for the benefit of the end user.
Several websites were described in a Webmaster World forum as having gone “from the heights of the Olympus to the depth of Hades” in the blink of an eye. Most of them didn’t have a clue on why they experienced such a considerable loss in the rankings. There were changes in the SERPs for Google.com and the local Google site with others experiencing different pages for the same query at the time.
While having duplicate content won’t get you a penalty from Google, the search engine does discourage it. It affects SEO since it splits the relevance of your content between two links which would have had a more significant impact on your website if all your pages had unique content.
Fortunately, you can spot duplicate content on the same domain. Here are typical instances to watch out for:
Meanwhile, duplicate content from different domains come in these forms: