301 redirect, canonical tag or hreflang – OK, hand over your heart, do you always know the difference? In the following text, we will explore the features that set them apart from one another.
Sometimes, you simply cannot prevent duplicate content from appearing on a website or on different (country) domains. There can be various reasons for this: starting with URL parameters, session IDs and printer friendly pages to the necessity to provide identical content on .co.uk and .com.
When it comes to duplicate content, search engines have a problem that is caused by many different reasons!
Which pages should they include in the index?
How should they work with the link metric? Which page should they raise in the ranking through inbound links?
Which page should they ultimately display in the search results?
I would now like to discuss four approaches that you can take to clearly tell search engines which URL should have a top priority.
By using redirect 301, you can divert all traffic and the SEO relevance of a page. But this will also mean that the old page from which users are redirected can no longer be accessed.
In 2009, Google introduced the canonical tag to solve this problem.
In contrast to a redirect 301, which reroutes all traffic AND the link juice of a page, the canonical tag diverts only the link juice. The page remains accessible on the Web and is thus the best solution for most applications.
Another way to create clarity about which page should be included in an index is to completely prevent one (or more) pages from being included. This option is created by the meta tag “noindex.”
Through the use of “noindex,” pages will indeed be crawled, but not added to the index.
The third way to create clarity for search engines in terms of duplicate content is to use the hreflang markup. With the help of this markup, pages are designated as simple language versions of another page. This helps search engines determine which page should be added to the index.
One point should be kept in mind here: Google and Yandex use the hreflang markup. By contrast, Bing uses meta tags to display the language.
Google offers other information designed to avoid duplicate content on its support page.