For example, the following URLs generally refer to the same file or web page:
But technically, these URLs are different. In most cases, these URLs return the same file, which is your home page. But technically, the host can return different content for these URLs.
When search engines want to normalize URLs, search engines need to pick the best representative of these choices. In general, your home page should be fixed, only one. But sometimes, on many websites, when the webmaster links back to the home page, the URL used is not unique. It is possible to connect to the URL http://www.domainname.com on your website and connect to the URL http://www.domainname.com/index.html for a while.
Although this will not cause any trouble for visitors, because these URLs are all the same file, it is a confusion for Google. Which URL is your real homepage? If there are many version URLs on your website, then both URLs may be included in the database by Google, which will result in the copy of the content page.
By copying a content web page, it is meant that the content of two or more web pages is the same or mostly similar. Many times, copying a web page may be a means of cheating. Even if it’s not a method of cheating, search engines usually only pick one of them to return search results, and the other duplicate pages are listed at the end so that they can’t be found at all.
When a URL normalization problem occurs on your website, it may cause a suspected copy of the web page, thus affecting the ranking of search engine results.
From Google’s point of view, they are developing the basic architecture of the so-called Big Daddy data centre to solve the problem of including URL normalization. But who knows if it can be solved?
From the perspective of the webmaster, you should do two things:
1) Your website uses only one URL when linking to other pages, especially the home page. Whether it is www or not, you only need to use one version from start to finish. This way the search engine knows which one is the normalized homepage URL.
2) But you can’t control which website to connect to your homepage. So you should redirect all URLs that are likely to be the home page URL to your home server URL on your host server. That is, from the following URLs
Have to do 301 redirects to this URL
It’s important to note that if your site has URL normalization issues, don’t delete one of the URL versions, especially the homepage, in the webmaster tool. For example, what you want is a version with www.
You must not go to the Baidu webmaster platform or Google webmaster tools to fill out the form, request no www website URL
Was deleted. Because of that, your entire domain name may be deleted.
Of course, there are other types of URL normalization issues besides including the two versions of www and not including www. For example, sometimes the search engine will remove or add the last slash at the end of the URL. Sometimes you will try to replace uppercase letters with lowercase letters, sometimes you may try to remove the session ID (session ID), etc., which may cause URL normalization problems.