We're building two web shops where one web shops sells one cosmetic brand, and second one that one and two others. Part of our blog posts, categories, products, product categories and pages is 100% same. We're aware of canonical link options but would like to know how serios is Google with penalties for duplicate content and how much of the content should we really rewrite to have it on the both of the web shops different.

3 Answers 3


There's not actually such a thing as a duplicate content penalty. See Google's 2008 post. This all still seems relevant from what I have seen.

If pages are too similar, what tends to happen is that Google choose one site as canonical and downplay the other. As such, if pages are identical then you should really re-write the content so that they are both indexed, though you should be fine launching and making these changes gradually.

If your sites are so similar that one site looks like scraped content, that's a different matter.

  • I wouldn't take anything Google says at face value. Specially after PageRank and the recent leak.
    – Daviid
    Commented Jun 17 at 7:11
  • I wouldn't trust them in regards of what ranking signals are used, but can't see any reason for them to temper the panic around duplicate content, and "which of these two pages is actually ranking" is observable in a way most signals are not.
    – RichardB
    Commented Jun 17 at 7:58

Google takes duplicate content seriously, as it considers it less valuable to users. Using canonical tags is a good start, but it's also helpful to rewrite some of the content to make it unique on each site, especially product descriptions and main pages like "About Us" or "FAQs". I think that at least 30-50% unique content on each site will look OK to Google.


I think the simple solution is to use code to generate the pages. I'd guess you're doing this anyway -- if you are displaying a catalog, they're probably not static pages but pages generated with ASP or JSP or PHP or whatever. At that point, just make the templates for the pages on the two sites very different. The product-specific info, like picture of the product and description, can be the same and drawn from the same database, but have different menus, headings, overall styles, etc.

I don't know what Google's algorithm for "duplicate content" is. It's probably not involved enough to try to separate out headings and menus et al from "core content".

  • It's easy enough to tell what core content is - it's the visible, machine readable text that changes on every page. The template is the bit that stays the same on every page. Changing styles will not solve duplicate content issues.
    – RichardB
    Commented Jun 17 at 18:51
  • @RichardB Assuming that Google checks for what "stays the same on every page", and is clever enough to distinguish changes to menus on different parts of the site, etc. Does Google go to that much work? Maybe. Does anyone actually know?
    – Jay
    Commented Jun 18 at 13:14

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