For the unification of domain names and SEO optimization, the ones with www and those without www are divided into two domain names. And search engines will also judge them as two domain names and treat one website as two identical websites. In this way It is very unfriendly to SEO. Most of the jumps made are 301 jumps, which permanently jump abc.com to www.abc.com. In this case, all the weight of the website will be concentrated on www.abc.com. .
First of all, let me state that it is indeed for SEO, because in search engines, the one with www and the one without www are two domain names, so one site will be understood as two identical sites in search engines. According to domain name classification, the domain name without www is a first-level domain name, and the one with www is actually a second-level domain name (but it is usually called a first-level domain name). In SEO, the weight and inclusion of first-level domain names are better than those of second-level domain names, but users Get used to visiting domain names with www (except for a few websites such as JD.com). As mentioned above, search engines understand that there are two sites with www and without www. However, if two identical sites are found, search engines will think that one is a mirror site (generally, the site with www will be affected, for the reasons mentioned above), so the ranking will be different. It will continue, but the user needs the one with www, so he can only discard the one without www, which is usually solved by 301 jump!
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For the unification of domain names and SEO optimization, the ones with www and those without www are divided into two domain names.
And search engines will also judge them as two domain names and treat one website as two identical websites. In this way It is very unfriendly to SEO.
Most of the jumps made are 301 jumps, which permanently jump abc.com to www.abc.com. In this case, all the weight of the website will be concentrated on www.abc.com. .
In this way, search engines will not regard the same site as two sites. As the two above said, it is beneficial to SEO
First of all, let me state that it is indeed for SEO, because in search engines, the one with www and the one without www are two domain names, so one site will be understood as two identical sites in search engines. According to domain name classification, the domain name without www is a first-level domain name, and the one with www is actually a second-level domain name (but it is usually called a first-level domain name). In SEO, the weight and inclusion of first-level domain names are better than those of second-level domain names, but users Get used to visiting domain names with www (except for a few websites such as JD.com). As mentioned above, search engines understand that there are two sites with www and without www. However, if two identical sites are found, search engines will think that one is a mirror site (generally, the site with www will be affected, for the reasons mentioned above), so the ranking will be different. It will continue, but the user needs the one with www, so he can only discard the one without www, which is usually solved by 301 jump!
Good for SEO
For SEO, for weight, and for Baidu to rank in the front
Login can also be a problem
Scenario
For example, if you log in to www.xxx.com and suddenly jump to xxx.com, you are no longer logged in.