¿Has your site an unknown clone ? How to find duplicate content

Hi, I'm WBear and I will talk you something about what is duplicate content on Internet for search engines and how it can be dangerous for your business if you don't take care 
 
What is Duplicate Content
 
There are 2 types of duplicated content, one is that content that are inside your own web site and it can be found in different sections/menus/areas, other type of duplicated content is text that is exactly the same on other domain/website. Both can be cloned partially and full copied into your site, lets go to see what is the difference of each one.
 
Search engine always take care about what content they will show to users after a search, this is a reason why search engines evaluate the quality of content before show it on search results.
 
How we can avoid to used duplicated content ?
 
If your are thinking on CMS, you will remember that there is impossible to avoid all duplicated content because always will be some module that is visible in different sections. But this is not to much important for search engine, in that web sites, the important part to take acre about duplicate content is the main body of the web, the area where the section information is loaded and showed to users.
 
There are some considerations to take care before the go-live of your web site:
 
Canonical link,
As described on Wikipedia a canonical link is and HTML element that prevent web developers owners to avoid duplicated content issues, this is also used if you work with any content management system or e-commerce style.
In that link you will find more information from Google, about how you can use or define canonical links in your site.
 
Redirect, moving to a new domain,
When you need to move your site from one domain to another you will need to notify Google and other search engines that you move the content to a new one with 301redirect as is indicated by Google in that link
 
Dynamic pages,
As I tell you before on dynamic pages there is always duplicated content and it is shown using url parameters, that change the behavior and the content of the site, to inform search engine about that you need to specify what parameters  need to be indexed and with non.
 
How you can detect of avoid the use of duplicated content in your web site:
The next list is only a few tool that I sometimes use to check duplicated content in web site where someone else write the content.

*The description of each tool is the meta information of each site, test it as your own consideration and select the best that work for your, there isn't any perfect tool for that, so you have to use what you need in each situation, I don't use the same in each analysis, I prefer to change the check method and compare the result of 2 different tools.

http://www.copyscape.com 
Copyscape is a free plagiarism checker. The software lets you detect duplicate content and check if your articles are original.

http://www.siteliner.com/
Free and fast analysis of your entire website - duplicate content, broken links, internal page rank, redirections and more. Also creates an XML sitemap.

http://www.plagium.com/
Plagiarism Tracker, Plagiarism Checker,Plagium, Plagiary, Plagiarist, Plagiarism, Fabrication, Falsification, Leech Finder, Source Tracker, Source Finder, Pirate Tracker, Copyright, Copyright Law, Unauthorized Use, Copyright Violation, plagiat, plagiats, plagier, détection de plagiat, droits d'auteur, deteção de plágio

http://www.similarsitesearch.com/
SimilarSiteSearch.com helps you find similar, related, or alternative websites. Our goal is to generate the most relevant results for our users.

https://www.google.com/webmasters/tools/
Finally we can see if there is duplicate content within our website with the tool for webmaster from Google, from it we can see it is if there are meta tags and titles H1 duplicates within the pages that make up the domain, if it detects that so it is best to correct this point those mistakes disappear.

That's all for now, non duplicated content will allow you a long time relevance on search engines and a good user experience for your audience. This is only a few information about how is identified by search engines duplicate content and the penalties about using it.
Quote from BBear: Copy quality content from top page ranks pages, copy it 100%, after you open the content to search engines, you have time before your site is banned to rewrite the content and change it, that will allow your some time of good result and when you change the content again it will give you a change notification to call search engine robots again.

Sources:
https://support.google.com/webmasters/answer/66359?hl=en
http://moz.com/learn/seo/duplicate-content
http://en.wikipedia.org/wiki/Duplicate_content
http://searchenginewatch.com/article/2049078/What-is-Duplicate-Content