I recently read an SEO blog post where the author was giving examples of how to improve the SEO of an e-commerce page.

One of the points the author made was to have a blog, such as blog.example.com where updates can be made.

I thought this would only have an effect on blog.example.com and not example.com/product-1.

Similarly do other areas of SEO work in the same way.

For example does a link to blog.example.com have an effect on example.com/product-1?


Subdomains are not considered in the website SEO scoring the same as subfolders are considered - they are treated as separate but related properties with a separate score/rank etc.

Therefore, having a blog at blog.example.com will definately influence the overall SEO/page ranks of your website at www.example.com, but not as much as if it were at example.com/blog. Links to and from subdomains from your main website would be treated as internal site links because the sites are so obviously related.

I would suggest this really is a duplicate question though - have you read:

  • 1
    You need to re-read these. Sub-domains are treated as separate sites, however, Google does recognize that a sub-domain is related to the parent domain and in some cases value such as trust metrics will be passed between the two. However, with a sub-directory, all value is given to the parent domain. I have described realms before which would include sub-domains of a parent and how they are viewed by search engines. Having blog.example.com helps blog.example.com and not example.com so much. Remember that trust metrics are assigned to the parent then extended to the sub-domain.
    – closetnoc
    Jan 27 '15 at 15:38
  • Yes well spotted @closetnoc - I get myself in a muddle on days like today. Answer amended, more caffeine required. Jan 27 '15 at 15:45
  • I know your heart was/is right! And that is the best starting point there is.
    – closetnoc
    Jan 27 '15 at 15:51
  • @closetnoc - So my given comment to this question is correct or not? please tell me so I can also get right direction if I am wrong. Jan 28 '15 at 4:20
  • 1
    @HelpingHands Generally sub-domains do not help the parent domain much if at all. But using a sub-directory does unless the content dilutes the overall topic. For example, a site on semantic search has a sub-directory on cat care can potentially dilute the subject of semantic search. This is where a sub-domains come in handy. If a sub-domain on cat care is created, it will not effect the website on semantic search.
    – closetnoc
    Jan 28 '15 at 5:35

According to moz, each website having two kind of authority. One is Page authority and other is domain authority. So if blog.example.com got a few backlinks, that will help the page to gain more authority also will improve domain authority.

When a website having a good Domain authority, all of it's pages likely to get better search ranking. So in that way, blog.example.com will help to gain domain level authority and which will helps any page from that domain to rank well on search result page.

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