Some valuable insights into why duplicate content on your website is a problem for Google. Work-arounds and suggested solutions are made, but please let us know your thoughts.

1. Duplicate Content Filters, Penalties and other
Content Minefields
27th March 2012

2. Search Quality – the Duplicate Content Headache
Google can’t afford a SERPs of;
4)Search engine optimization
Search engine optimization (SEO) is the process of improving the
visibility of a website or a web page in search engines........
2) Search engine optimization
Search engine optimization (SEO) is the process of improving the
visibility of a website or a web page in search engines........
3) Search engine optimization
Search engine optimization (SEO) is the process of improving the
visibility of a website or a web page in search engines........
4) Search engine optimization
Search engine optimization (SEO) is the process of improving the
visibility of a website or a web page in search engines........
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3. Resource – the Duplicate Content Headache
Duplicate content has consequences for SE in;
Wastes Crawler resources - finite number of crawlers
Wastes Bandwidth – how often can you crawl 1 trillion documents and
keep your index fresh?
Increases Query CPU time – how do you search 1 trillion documents as
quickly as possible?
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4. Document importance – Duplicate Content Headache
Duplicate content can be a signal of an important document;
• Song lyrics
• Scholarly texts and historical documents, eg the Bible (1,000 pages)
• The Linux manual (2,000 pages)
• Breaking News – Associated Press, Reuters
etc.
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5. Types of Duplicate Content
Duplicate content comes in many forms
Intentional vs non intentional
On-site vs off-site
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6. On-Site Duplicate Content (Impacts Quality Score)
Intentional
• Printer friendly pages
•Different font sizes
•PDF documents
•Archive (non graphics versions)
•Shopping filters (sort by and pagination)
•RSS feeds
Non-intentional
• Affiliate URLs - www.example.com/?btag=123
• Adwords Campaigns - www.example.com/?utc=google
•Search results
•www vs non www URLs
•https vs http
•Stubs/plugins
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7. On-Site Duplicate Content (Impacts Quality Score)
10’000s of stub pages worst case scenario example;
This was 2 weeks after Andy had removed the duplicate links from the search pages on our advice eg;
http://www.motors.co.uk/Ford-Escort-0-9999999---2
http://www.motors.co.uk/Ford-Escort-0-9999999--U-2-
http://www.motors.co.uk/Ford-Escort-0-9999999---2%20-
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8. Off-Site Duplicate Content (Filters and Penalties)
Intentional vs non-intentional somewhat grey
Domain branding eg .com, .co.za
(Mobile website)
Content syndication
Content theft
Staging websites a common problem!!
Quality signals are often used to filter off-site Duplicates!!!
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9. How Does Google Filter Off-site Duplicate Content
Authors feel they have a right to rank for their own content –
Google’s Loyalty is to its users!!!
Google doesn’t necessarily reward a source or original but assesses;
• Relevance (eg is an article in context)
• Domain authority & links (eg Google Knol, Facebook)
• Fresh content boost
• Site quality signals (eg internal duplicate content!!!)
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10. Examples of Off-site Duplicate Content and Quality
Client with .com.au and a .com with https duplicates
Casino Client with a
lot of stub pages
(pre Panda)
Casino site
– severe health issues;
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11. How to Diagnose (on-site) Duplicate Content
Link building will exacerbate duplicate content indexing
Keep an eye on indexed pages (weekly) and look for spikes in Google
Indexing, (Yahoo and Bing)
Look for site:example.com
duplicates
Use Xenu link checker
Heed any Webmaster Tools warnings
Check your crawling and cache dates
Frequent update but stale cache dates = dupe content issues
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12. How to address on-site and off-site duplicate content
You have a whole armoury of potential tools including;
Robots.txt exclusion
Robots meta tag
Canonical tag
Webmaster URL exclusion
Password protection
(301 redirects)
(File a DMCA against serial content thieves?)
Lot of well-meaning people give bad advice though
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13. Google Engineers Can’t Agree

14. Adam Lasnik – “Deftly Dealing with
Duplicate Content” 2006
Probably the authoritative guide to duplicate content;
• What is duplicate content?
• What isn't duplicate content?
• Why does Google care about duplicate content?
• What does Google do about it?
• How can Webmasters proactively address duplicate content
issues?
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15. Deftly Dealing with... - Our advice/experience
Robots.txt
Routinely ignored by Google, probably because of malware
User-agent: *
Allow: /the-good-stuff/
Disallow: /the-malware/
Robots.txt is ignored unless combined with emergency Webmaster
Tools URL removal (3 months)
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16. Our advice/experience
Canonical tag
Works great for cross-domain duplicate content
Largely ineffective for pagination eg shopping sites
Totally ineffective unless canonical URLs are VERY similar if not identical
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17. Our advice/experience
Robots Meta Tag
Noindex,Follow - 100% obeyed by Google and passes Page Rank too
Very effective for pagination eg shopping sites
Works well for tracking links too (www.example.com/?affid=123456)
Doesn’t work when used with blocking robots.txt
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18. Our advice/experience
Password Protect/htaccess 403 Forbidden
Works great for staging sites
Stubs - Problem in that it generates Webmaster Tools errors
Our feeling best to avoid on your main domain
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19. Extreme Techniques to Avoid Dupe Content
Make all your backend .exe
with htaccess

20. Summary
Duplicate content is a minefield!
Filters usually apply, penalties are very rare
You have the answer in your own hands
Stay on top of your site’s health – especially internal duplicate content

21. Thank you for your attention!
Thanks to:
Anton Groeneveldt
Carla dos Santos