I have a website xxx.example.com whose content is unrelated to www.example.com - My SEO person has provided evidence that xxx.example.com is causing a drop in SEO for www.example.com for keywords of interest at www.example.com.

Short of moving xxx.example.com to another domain, is there a way I can advise Google that these subdomains should be treated entirely separately?

  • I am curious to know the reason for the drop? Do the sub domains compete for same keywords?
    – Kannan
    Jun 20, 2021 at 7:37
  • @Kannan Sites are entirely different. One is promoting a business (nothing to do with IOT), the other is a personal blog with general things, quite a bit IOT related. Apparently GMB or whatever tool the SEO person is using shows that subdomain pages as associated with the main site - even though there are no links between them (Subdomain does not link outside its domain, and had no contact information on it). I've pushed the subdomain to a new domain, but I expect the issue will recur when other family members also use subdomains of this new domain name.
    – davidgo
    Jun 20, 2021 at 7:56

1 Answer 1


Context: You have now moved xxx.example.com to a new domain and now are worried about the future sub-domains of the new domain.

I just went through Do subdomains help/hurt SEO?

I could find a relevant piece of information that could help in your case.

A highlighted quote from Vanessa Fox, an ex-Google employee, is this

Primary domains can pass a penalty to subdomains. Subdomains can’t pass a penalty to a main domain unless the main domain holds a clear relation to the subdomain.

So, a good solution will be to host the moved website in the root domain (without www in case you are using).

  • thank you for attempting to answer. Unfortunately that answer is from 2010, and is no longer applicable. In fact, if you click on the link in that answer, it has been updated and now says "Google ranks subdomains more or less the same as subdirectories (also referred to as subfolders).", but the answer then goes on and is all-over the place and contradictory!
    – davidgo
    Jun 21, 2021 at 7:23
  • Sorry, my bad. But still, I am getting a feeling that penalty may not go upstream from a logical viewpoint. Else, hosting platforms like WordPress and Blogger may accumulate penalties for not of their fault. But I couldn't find an answer from an authoritative source yet.
    – Kannan
    Jun 21, 2021 at 11:30

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