How do search engines deal with duplicate content?

Search engines deal with duplicate content by filtering it out and only showing one version in search results.

Search engines, such as Google, have sophisticated algorithms designed to identify and handle duplicate content. When the same or very similar content is found on multiple URLs, it's considered duplicate content. This can occur within a single website (internal duplication) or across different websites (external duplication). The search engine's algorithm will then filter out the duplicates and choose one version to display in the search results. This is done to provide users with diverse search results and a better browsing experience.

The process of dealing with duplicate content begins with the crawling and indexing of web pages. Search engines use web crawlers, also known as spiders or bots, to discover and index new and updated content. When a crawler encounters duplicate content, it must decide which version is most relevant to a user's search query. This decision is based on various factors, such as the overall quality of the website, the site's perceived authority, and the number of links pointing to the page.

Once a version has been selected, it's included in the search engine's index and can appear in search results. The other versions are not deleted or penalised; they're simply filtered out of search results. However, it's important to note that excessive duplicate content can lead to a lower ranking in search results, as it can be seen as a sign of a low-quality website.

To help search engines identify the preferred version of a piece of content, website owners can use canonical tags. A canonical tag is a piece of HTML code that specifies the 'canonical' or preferred version of a web page. This helps search engines understand which version of the content to include in their index and display in search results.

In conclusion, search engines deal with duplicate content by identifying it, filtering it out, and choosing one version to display in search results. This process is guided by complex algorithms and can be influenced by website owners through the use of canonical tags.