Oameni buni, asa numitul "duplicate content" poate atrage penalizari pentru site-urile care au acelasi continut ca si alte site-uri (cele care fac scraping, sau fura continut). Continutul duplicat in interiorul unui site, nu atrage dupa sine penalizari, dupa cum spune chiar si Google aici: http://googlewebmastercentral.blogsp...t-penalty.html

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But most site owners whom I hear worrying about duplicate content aren't talking about scraping or domain farms; they're talking about things like having multiple URLs on the same domain that point to the same content. Like http://www.example.com/skates.asp?co...&brand=riedell and http://www.example.com/skates.asp?br...ll&color=black. Having this type of duplicate content on your site can potentially affect your site's performance, but it doesn't cause penalties.
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This type of non-malicious duplication is fairly common, especially since many CMSs don't handle this well by default. So when people say that having this type of duplicate content can affect your site, it's not because you're likely to be penalized; it's simply due to the way that web sites and search engines work.
Google vede continutul duplicat in interiorul siteului tau (ex: acelasi continut sau continut in mare parte similar la 2 url-uri diferite ale aceluiasi site) si alege una dintre pagini ca fiind relevanta pentru o anumita cautare, si o afisaza mai sus in SERP.

Mi se pare un lucru de bun simt, si corect pentru toata lumea (Google, webmaster, user)!