Most webmasters already know that duplicate content can have a negative impact on a website's rankings. But how can you check if a particular website has this problem, and how can you reduce or avoid it?
From the outset, duplicate content can be divided into two main categories:
Duplicate content due to website structure
Duplicate content due to content theft
About duplicate content caused by website structure
Some website structures inherently cause duplicate content, examples include:
ptint-friendly pages
Have generally similar content on multiple pages that can be accessed through different URL addresses
There are very similar units on the page, such as a series of different colored linings with similar descriptions in an e-commerce category
The page is part of a membership program for a tracking application, and the program is configured incorrectly
Multiple pages have duplicate titles or duplicate meta tag values
Use session ID in URL address
Standardization issues
In order to find duplicate content caused by the website structure, you can use the site:www.yingyuxuexi.org.cn query string to check the URL addresses of websites that have been indexed by search engines. All major search engines (Google, Yahoo!, Microsoft Live Search) support this feature. Typically, "print-friendly" pages will appear quickly if they are indexed.
Google often places what it considers to be duplicate content in a "supplemental index." There is a supplementary material mark at the bottom of the search engine results, and this content is placed. Of course, Google has now hidden this logo. If a Web site has many pages appearing in the supplemental index, it may mean that these pages are duplicate content—at least, Google thinks so. If possible, research the URL addresses of these pages and look for any of the above situations. Look especially at the pages that follow the results. Duplicate content problems are particularly easy to create if you're not careful, so it's useful to look at them from a search engine-friendly perspective.
About duplicate content due to content theft
Content theft creates an entirely different problem. Just as thieves can steal real property, they can also steal content. No doubt this is the reason why it is called content theft. This creates problems for search engines, which, because they work hard to filter out duplicate content from search results (and from different websites), sometimes make misconceptions about what is original and authoritative content.
In some cases, this is a hidden problem and can have a disastrous impact on rankings. If you have been a victim of content theft and want to take action, start by sending a cease and desist letter to the person using the illegal content. You can use the contact information provided by the website, or the contact information in the WHOIS record for the domain name. If this fails, approach major search engines to warn them of content theft.
Here are the URL addresses that major search engines are responsible for:
Google: http://www.google.com/dmca.html
Yahoo!: http://docs.yahoo.com/info/copyrighffcopyright.html
Basically, as long as a website insists on constantly updating original content, search engines such as Baidu, Google, and Yahoo can already well identify the original source of the original content. What the webmaster needs to do is to update high-quality website content every day.
Author: Street Dancer-HipHop-China's largest dancer communication platform Source: http://www.jiewuzhe.com