Duplicate content is a regular topic among those dealing with search engine optimization. The consensus is difficult to get, some say there’s not much to risk. Some take this way more seriously and try to avoid duplicate content whenever they can. As it is most of the time, the truth is somewhere in between. One can go through the official responses by Google, lately they’ve chimed in again and somewhat eased the worries of many webmasters.
“Duplicate content kills your rankings” this is quite a frequent sentiment one can read over and over. This leads to many webmasters trying to avoid even short segments that would include duplicated text. Also the usage of tags and categories (such as in WordPress) makes some uncertain. This topic scares webmasters all around the place.
Johannes Müller from Google knows the topic very well, in a recent Google Webmaster Hangout, he laid out the basics when it comes to Google and duplicate content: According to Müller, it’s nearly impossible to put together a website that would not include duplicate content. This way Google does recognize, if the duplicate content is for example auto-generated as categories pages.
Duplicated content is then indexed and rated by Google, to recognize which part should be shown in the search results. Therefore just a one out of the duplicate content parts is shown in the search results, one that’s deemed the most relevant. While it still does pay off to bet on original content, if there would be duplicate content within a site, maintaining a natural structure, it is not a straight reason for a penalty.