Duplicate content is text that appears, in full or very nearly, at more than one URL, either within your own site or across different sites. Search engines then have to decide which version is the original and which one to show, and they do not always choose the one you would.
How duplicate content works
When Google finds several URLs carrying the same main content, it groups them into a cluster and picks one as the canonical: the version it indexes and ranks. The others are usually left out of results. Google makes that choice from a mix of signals, including any canonical tag you have set, redirects, internal links, which URL appears in your sitemap and whether the page is served over HTTPS.
Most duplication on small business sites is created by the software, not by anyone copying text. Common sources:
- The same page reachable at http and https, or with and without www.
- Tracking and filter parameters, such as ?utm_source=newsletter or ?colour=blue&sort=price, each producing a new URL.
- Product variants given their own pages with identical descriptions.
- Printer-friendly versions, tag archives and paginated category pages repeating the same introductions.
- A staging site left open to crawlers.
- Articles syndicated to another publisher without a canonical or a link back.
Near-duplicates are the harder case. A Kent roofing firm with twenty town pages that differ only by the town name is the classic example: Google sees almost the same page twenty times and may index only a handful.
Why it matters
Google has said repeatedly that duplicate content on its own is not grounds for a penalty. The damage is quieter. Links and internal signals get split between several versions instead of building up on one. Crawlers spend time fetching copies rather than your new pages, which matters more as a site grows. The URL that ranks may be an ugly parameter version or an old page you meant to retire, and your reporting becomes harder to read because traffic is scattered across addresses.
The exception is deliberate copying. Pages built by scraping or lightly rewriting other people’s content, or by stamping out hundreds of near-identical location pages, fall under Google’s spam policies, and that can lead to whole sections being demoted.
Common mistakes
- Using noindex where a canonical belongs. Noindex drops the page but does not pass its signals on to the version you want.
- Canonical tags that contradict everything else. If the tag says one URL but your internal links, sitemap and redirects all point at another, Google may ignore the tag.
- Templated location or service pages. Changing only the place name produces near-duplicates, not new pages.
- Manufacturer descriptions. UK retailers selling the same branded products as dozens of competitors often all publish the identical paragraph, so none of them gives Google a reason to prefer their page.
- Blocking duplicates in robots.txt. A blocked URL cannot be crawled, so Google never sees the canonical tag on it.
How to act on it
Start with Search Console’s Page indexing report and look for “Duplicate without user-selected canonical” and “Duplicate, Google chose different canonical than user”. Then crawl the site and compare page titles and body text to find clusters. For each cluster, decide whether the pages should exist separately at all. If they should not, merge them and redirect. If they serve the same content for a technical reason, set a self-referencing canonical on the preferred URL and point the variants at it. If they target genuinely different needs, rewrite them so each says something the others do not.
Duplication caused by the platform, such as parameters, faceted navigation or protocol variants, is usually fixed once at template or server level. That is routine work in technical SEO, and it often clears up apparent keyword cannibalisation at the same time. Where pages are near-empty as well as repeated, treat them as thin content and decide whether to improve, combine or remove them.