What Is Duplicate Content, and Does It Actually Hurt SEO?

Duplicate content means the same, or nearly the same, text appears at more than one web address. It has a scary reputation, but for most sites it's more about confusion than punishment.

Is it really a penalty?

In ordinary cases, search engines don't punish a site for it. They pick one version to show and ignore the rest. The risk is that they pick the wrong version, or split the ranking power between copies so none of them performs as well as one strong page would.

Where it usually comes from

• The same page reachable with and without www, see www vs. non-www
• Both a trailing-slash and non-trailing-slash version, see trailing slashes
• Near-identical pages for each location where only the city name changes, see pages per location
• Product or service descriptions copied from a supplier

How to fix it

Redirect the extra versions to the one you want, and use a canonical URL where redirects aren't practical. For similar pages, rewrite each one so it says something genuinely different and useful.

The takeaway

You don't need to panic about every repeated sentence. Focus on making sure each important page lives at one address and says something worth reading on its own.