Google Classifies Subdomains As Part Of The Main Domain Now

Sep 1, 2011 • 9:35 am | comments (28) by twitter Google+ | Filed Under Google Search Engine Optimization

Google WebmasterThe Google Webmaster Blog announced a significantly large change to how Google Webmaster Tools classifies subdomains.

Prior, subdomains would be considered separate sites and thus a link from a subdomain would be considered an external link by Google, in Google's reports. Today, Google is changing that and now considering those links internal links.

So when I link from to, that is no longer a link from an external domain, it is a link from an internal domain.

Google explained:

Most people think of and as the same site these days, so we're changing it such that now, if you add either or as a site, links from both the www and non-www versions of the domain will be categorized as internal links. We've also extended this idea to include other subdomains, since many people who own a domain also own its subdomains-so links from or will also be categorized as internal links for

Here is the table they used to explain it:

Links for linksInternal links
Previously categorized
Now categorized

So does this impact how Google treats links from subdomains in their link algorithm? I think so. Hubpages played on it and said it helped with Panda.

Does this mean that Google will list less of your subdomains in the search results as individual results? Well, yea - they have already with the new mega sitelinks, which interestingly doesn't apply for a search for [google].

In any event, keep note of this significant change, not only to the reports within Google Webmaster Tools but to how it defines the search results, linking algorithms and so on.

Forum discussion at WebmasterWorld.

Update: Google has clarification that this does not impact rankings. See more details over here.

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09/01/2011 01:51 pm

I'm so pleased I found your website and now following you here and on Google +1.  The information you share will help me easily keep up-to-date.  Thanks.


09/01/2011 02:02 pm

The ownership of the domain and subdomain is what I take away from this change. However, in time I am sure  subdomain ownership methods will evolve to enable subdomains to count as external links. GOOG has just made the rules known.

Kes Phelps

09/01/2011 02:04 pm

So how does this effect external links from a sub-domain? If and link to will a link from now be devalued since already has 2 links from

David Iwanow

09/01/2011 02:36 pm

so how are they going to deal with the millions of sites??? surely they are looking at manually overriding some of the rules for big generators of subdomains and does that mean less SEO benefit from 301 the non-www version of your sites?


09/01/2011 02:56 pm

Great article Barry.


09/01/2011 02:59 pm

Weird. Does that mean anyone who spent time doing link building on all those free Wordpress sites is going to cry? :)

Malcolm Slade

09/01/2011 03:18 pm

Erm, am I the only one who has read this as: To help people who also run sub-domains look at their existing external backlinks we have moved sub-domain links in to the internal link data rather than external. I see no evidence of "Google have changed the way we classify sub-domain links". It seems to be just a data visualisation tweek within GWT. 


09/01/2011 03:18 pm

This means i don't have to worry about being less optimal than anymore, right?

MIke Suh

09/01/2011 03:21 pm

i think this covers it "Prior, subdomains would be considered separate sites and thus a link from a subdomain would be considered an external link by Google, in Google's reports. Today, Google is changing that and now considering those links internal links."  makes me think its more than just a front end tweek

Scott Thomas

09/01/2011 04:48 pm

Seems to make sense to me - close a loophole. 


09/01/2011 05:55 pm

I'm wondering the same thing.  

Jeanne Kardell

09/01/2011 07:54 pm

I also agree it that it makes sense - really all part of the same domain so why should they count as external links.


09/01/2011 11:47 pm

I have to agree. I think this is a WMT tools interface change, not an algo or link value attribution change. All I read into this is that link reporting in WMT is changing as to what shows up in external or internal links


09/02/2011 07:00 am

yeah, you would have to think a lot of exceptions would be made for "known" instances of a domain NOT representing "the same site"....blogspot, posterous, wordpress, tumblr, etc, etc


09/02/2011 12:19 pm

Interesting post... Thanks for sharing... Great conversation below... I can really learn a lot...


09/02/2011 01:39 pm

I have a question, then to make SEO a sub-domain is as if we were positioning the main domain folder? Recall that before the SEO to start playing a sub domain of 0.   Greetings.


09/02/2011 03:50 pm

I read the original announcement at WMT, and assumed it was just the way they were SHOWING our links.  After reading this, you seemed to be saying that it was a reclassification - i.e. algo shift?  - or maybe I read that into the word "classifies" Anyway, this morning suzukik on the WMT thread says  this - "This change is only for the report on Webmaster Tools. It has not changed an algorithm of web search. I heard this just now from John Mueller of Google on video chat of Google+. "

Rob woods

09/03/2011 01:21 am

Hi mike, DMed you but I really think this is just a reporting change, not an attribution change.

Jon Cooper

09/03/2011 01:43 am

In all honesty I'm surprised this is now just happening. I would say one thing - certain websites such as and should be the exception to this rule. Anyone agree?

ICTExpress ICTExpress

09/03/2011 05:49 pm

Good for seo Thu thuat seo


09/05/2011 06:31 pm

We'll have to resurrect Einstein figure that out LoL!


09/06/2011 05:20 am



09/06/2011 09:52 pm

There is no "devaluing" going on. This is simply a reporting change. (Read the update.) Google still treats subdomains as mostly-separate entities for ranking purposes, but they now include links between subdomains as internal links in reports found in Webmaster Tools. Links from other domains are still considered to be external, and in the case you give as an example, links to another domain from two subdomains of the same parent should be considered to be two inbound links from separate entities, for the purposes of ranking.

Joe Williams

09/12/2011 10:55 am

I am not sure how confident I feel about this. Any one remember a similar announcement four years ago?


11/04/2011 07:55 pm

Not a bad change, i would say!

Mike Dammann

04/02/2013 10:05 am

Isn't one of the reasons to build on a subdomain to have the freedom of choosing different subject matters without diluting the keyword density of the main site?

Habeas Corpus Canada

04/11/2013 09:28 pm

Google's deeming subdomains as internal links of the main domain is extremely BAD for the millions of people who build their web sites in Free Hosts such as -- The subdomain is your free site's name, and if ANY free site hosted in happens to have malware or virus issues, for example, or is deemed as an "attack site" (arbitrarily by the self-imposed judgment of Google) -- YOUR free site is shut off by Google and its partners such as FireFox, and is labelled an "attack site"! It has happened to me. My kids' poetry site was called an "attack site". Talk about ruining your reputation! My kids' poetry site was labelled as an "attack site" by Google and Firefox, completely falsely and unfairly, because a totally different web site, not owned by me, and unknown to me, which was also a member of, happened to have done something which Google didn't like. As a consequence, ALL member sites in WebNG were falsely (and I say abusively) tarred with the label "attack site". This is just totalitarian mass-defamation, because ALL member sites in WebNG were falsely (and I say abusively) tarred with the label "attack site". Google needs to reverse this policy, it's blatant abuse of millions of innocent people hosting innocent and legitimate web sites -- punishing us ALL for what one may do wrong in a million members. And we millions of innocents have no control, and even no knowledge of WHO the guilty -- or allegedly guilty -- party is.

hareesh choudhari

08/27/2013 10:39 am

Nice article Barry :) Can you let me know how can I avoid search engines not to crawl my sub domain links? Thanks

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