Another cause of duplicate content is the use of URL parameters that do not change the content of the page, such as in tracking links. You see, to a search engine, URLs are not the same :.exampleomkeyword-xas :.exampleomkeyword-x?source=rssURLs. The latter may allow you to track where people are coming from, but it may also make it harder for you to get good rankings - a very unwanted side effect!
This doesn’t just apply to tracking parameters, of course. It applies to every parameter you can add to a URL that doesn’t change important content, whether that parameter is for “change the sorting of a group of products” or “show another sidebar”: all of these will result in duplicate content.
Unauthorized use
Most causes of duplicate content are "errors" on your kazakhstan mobile database part or your site's part. However, sometimes other sites use your content with or without your consent. They don't always link to your original article, so search engines don't "get" it and have to deal with another version of the same article. The more popular your site is, the bigger this problem becomes.
Parameter Order
Another common reason is that the CMS does not use nice clean URLs, but instead uses URLs like ?id=1&cat=2, where ID refers to the article and cat refers to the category. The URLs ?cat=2&id=1will render the same in most website systems, but will be completely different to search engines.
Comments Pagination
In WordPress, as well as some other systems, there is an option to paginate your comments. This results in content being duplicated in the post URL, article URL + comment-page-1, comment-page-2etc.