At Google’s webmaster central blog, they’ve posted an interesting article about how Duplicate Content Penalties work in reality – the short version; it doesn’t even exist.
Here are some snippets:
Let’s put this to bed once and for all, folks: There’s no such thing as a “duplicate content penalty.” At least, not in the way most people mean when they say that.
There are some penalties that are related to the idea of having the same content as another site—for example, if you’re scraping content from other sites and republishing it, or if you republish content without adding any additional value. These tactics are clearly outlined (and discouraged) in our Webmaster Guidelines.
They rap it up, by stating:
In summary: Having duplicate content can affect your site in a variety of ways; but unless you’ve been duplicating deliberately, it’s unlikely that one of those ways will be a penalty. This means that:
- You typically don’t need to submit a reconsideration request when you’re cleaning up innocently duplicated content.
- You can help your fellow webmasters by not perpetuating the myth of duplicate content penalties! The remedies for duplicate content are entirely within your control.
- If you’re a webmaster of beginner-to-intermediate savviness, you probably don’t need to put too much energy into worrying about duplicate content, since most search engines have ways of handling it.
Here are some other interesting posts about this topic: