Duplicate content: is there really a penalty?

What is duplicate content?

Identical or very similar content that can be reached at several addresses, for example with and without “www”, with parameters or as a print version. Similar text across many pages counts too.

Is there a penalty?

By its own account, Google does not usually penalise duplicate content, as long as there is no intent to deceive behind it. It chooses one version to display. The problem is that it is not necessarily the one you want.

Typical causes and solutions

• Several addresses for the same page: Decide on one version and redirect the others with a 301 redirect.
• Parameters and filters (shops): Set a canonical tag pointing to the main version.
• Similar text blocks on many pages: Make the pages distinct in content or merge them.
• Manufacturer texts copied across: Add your own texts.

Conclusion

No need to panic, but do put things in order. One page, one topic, one address. More on canonicals in Canonical tag explained.