Of all the topics that are discussed within the SEO blogosphere, one of the topics that creates the most controversy and disagreement is that of duplicate content. I think one of the reasons that there are so many different viewpoints surrounding this issue is because there are multiple ways that people define the phrase “duplicate content.”

Since I always believe in going straight to the source, let’s find out what Google has to say about duplicate content. According to Google, “Duplicate content generally refers to substantive blocks of content within or across domains that either completely match other content or are appreciably similar.” Now that we have Google’s definition of duplicate content, let’s look at what they have to say on the issue of how it can impact a website’s ranking:

“Mostly, this is not deceptive in origin.”

“However, in some cases, content is deliberately duplicated across domains in an attempt to manipulate search engine rankings or win more traffic. Deceptive practices like this can result in a poor user experience, when a visitor sees substantially the same content repeated within a set of search results.”

“Duplicate content on a site is not grounds for action on that site unless it appears that the intent of the duplicate content is to be deceptive and manipulate search engine results.”

So, if you actually look at what Google is saying about duplicate conent, their stance is that you will only be explicitly penalized if they feel the duplicate content you are publishing is intended to deceive users or manipulate their search results. An example of this would be a Made for AdSense (MFA) website, which only contains content from other websites. The only purpose of a MFA website is to attract visitors who will click the AdSense ads.

If you are wondering how Google judges content and determines malicious duplicate content, this illustration from Elliance (which was published on Search Engine Land) should make that process clear to you:

Search Engines Duplicate Content

Now, while you may think that I’m taking the “duplicate content doesn’t matter” stance, that is simply not true. Even if you aren’t publishing duplicate content with malicious intent, you may still run into problems. For example, I think Dave Feldman really hit the nail on the head in his post on SEL earlier this year, which was titled Got Duplicate Content? Don’t Let It Dilute Your SEO Efforts. The main focus of his post was that even when duplicate content isn’t published with malicious intent, it can still hurt your site’s rankings by diluting the weight of your links. Here’s the example he uses:

“Let’s say you have 30 external sites lined up to provide a link to your site; you just need to tell them what page to link to. If all 30 of those links point to the hiking boots page in the Men’s Clothing section, a good deal of link value will be passed to that page.

However, what happens if those 30 links get divvied-up across three different versions of that page, and are split between Men’s Clothing, Footwear, and Outdoors? Potentially, each page would only get 33 percent of that total link value. Clearly, 100 percent would be better.”

In addition to link dilution, the other major area where duplicate content can cause issues is with affiliate websites. As you may know, Google is getting more aggressive in their filtering of “thin affilaite websites” (which are affiliate websites with little original content). Not only can you run into problems with their algorithm, but if your website is hand reviewed by Google, a lack of original content could cause you to fail that review (and thus incur some form of a ranking penalty).

While the duplicate content debate will inevitably continue, at the end of the day, you can avoid a lot of potential headaches and worries by simply creating some form of content that is unique and useful to visitors.