Duplicate content is a problem which many bloggers and webmasters care about. The reason is that duplicate content can harm your search engine rankings in the long term.
The block of contents that are similar under the same or different domains can be referred to as duplicate content. However, Google doesn't treat some contents as duplicate in some cases. Like, same article in different languages and occasional snippets (quotes).
When Google encounter with duplicate contents, it's algorithm filter the result of a search because Google wants to provide its users with the unique contents as much as possible. At the time when Google spider crawls a website, it tries to index and show pages with unique informtion. Higher priority is given to the contents that are index at the beginning. This is why we call "Content is the king" in the process of SEO.
So, how can you avoid duplicate content issues in your site?
- Make changes in your robots.txt file. Let the search engines know which pages are to be indexed.
- Always use the same url to link to a page within your site.
- If your content is in Russian language, use top level domain such as .ru
- Set the option whether you prefer with or without www at Google's Wemaster Tools. Google treats the site with www and without www differently.
- If other webmasters use your content, make sure they link back to your original one.
- Don't include the lengthy text at every page. Better to create a seperate page and link to it.
- Make sure if your Content Management System doesn't publish the same content in various formats.
Duplicate content is a problem that every webmaster deals with. If your content is being published in other websites without your permission, you can notice it to Google by filing a DMCA request.