Do low quality subdomains affect the ranking performance/quality of a root domain?

[paulissai]

Hi,

Late last year the company I work for launched two new websites that, at the time, we believed were completely separate from our main website. The two new websites were set up externally and were not well-planned from an SEO perspective (LOTS of duplicate content) - hence, they have struggled to rank on Google.

Since the launch of the new websites we have also noticed that our main website (that previously ranked very well) has suffered a decline in visitation and search engine rank. We initially attributed this to a number of factors, including the state of the market, and ramped up our SEO efforts (seeing minor improvement). We have since realised that these two new websites have been set up as subdomains of our main website, with MOZ displaying the same domain authority and root domain backlink profile.

My question is, do poor quality subdomains affect the ranking performance of a root domain? I have not yet managed to find a definitive answer.

Please let me know if more information is required - I am quite new to the whole SEO concept.

Thanks!

Amy

[PatrickDelehanty]

Hi Amy

Subdomains CAN impact root domain performance, it's just a matter of how they interact. But it's odd that your sub domains are performing fine, but your root domain is seeing the impact. That just sounds odd to me.

I will have to do a little more research on your particular site to see if I find anything else. Thanks for your patience in my response on this one!

[MattAntonino]

Let's put it this way, if I owned Wordpress (or a smaller blog company) and it had two sites and one was going to get a penalty and the sites were:

http://mysite.wordpress.com

http://www.wordpress.com/mysite

I would want the subdomain penalised.  I don't think it's going to pass through to my main domain. I am nearly certain the subfolder will in 95% of cases.

@Patrick - I do agree with you but Wordpress is a very public example of tons & tons & TONS of spammy subdomains ranking just fine. I think the size of the subdomains is in proportion to their links so if a million subdomains are penalised, even on Wordpress.com, I think you'd see effect if there was going to be one.

[paulissai]

Hi Matt and Patrick,

Correct me if I'm wrong but is the general consensus that there is no definitive answer on this topic - that a subdomain's impact on a root domain is indeterminate?

Thanks

[PatrickDelehanty]

Hi Matt

While I understand what you are trying to say here, I think that Wordpress isn't the best example. Reason being - everyone uses Wordpress; according to W3C & BuiltWith, it's the CMS with the biggest market share by a long shot - here is BuiltWith's stats.

Keep in mind, for broad search terms like "blog", big name & authoritative brands are going to rank, that's just the way it is. Wordpress is associated with "blog" and topics like "content management system"; they are constantly referenced & mentioned in "best to use" lists and have been for years and will continue to be. This is also echoed in Searchmetrics 2014 Ranking Factors Studies. Brands rank for broad terms, while smaller sites rank for long tail. (Keep in mind, I understand this is a study, and we all know how those can be, especially for ranking factors)

We are talking about a big brand getting ranked for a general term - that's just the name of the search game. But again, I totally get what you're saying here.

[paulissai]

• Very good question Patrick!

  The parts website was developed first as our parts business is quite successful and management was looking for a more efficient way of supplying parts to our customers. The other e-commerce website was conceived shortly after and was rushed to completion - this website is the one with the most issues from an seo perspective. The marketing team did not have a significant hand in the development of these sites (you might notice they are quite different to our main website).

  To answer your question, yes, we also acknowledged that one subdomain would be better and the parts website will shortly be migrated to the main e-commerce website. We are pooling all our resources into fixing up the shop.caps.com.au site. It was only last Friday that we realised that the two new sites are actually subdomains of the root domain (why we didn't realise this earlier is beyond me) and could be a factor in why it has suffered declining rankings and traffic.

  I have read conflicting accounts on whether or not subdomains directly affect root domains - some schools of thought said no, they are ranked independently and are viewed as separate sites by Google, while others said yes or maybe. Could you perhaps provide me with a reference of where you base your view that it can/does affect the root domain?

  If the subdomains are the cause of our main site's declining performance, would it be best that we move them to a different domain or should we leave it as is and continue with our plan to migrate the parts site (this will happen regardless) and focus on fixing up the shop.caps.com.au site?

  Sorry for bombarding you with questions - this entire thing has been quite confronting and confusing considering this is my first marketing role out of college!

  Thanks

[paulissai]

Hi Matt-POP,

This has played on my mind as well. That is where my doubts that our issues are solely caused by our subdomains stem from.

I guess, in a sense, I am hoping that it is the subdomains because it would present a simple solution.

I am afraid of making any grand decisions, like removing the subdomians, without considering the possibility that we are doing something else wrong, but I'm yet to discover another clear cause.

[MattAntonino]

While I do agree it's possible for them to affect you, I want you to think about an example.

Take the keyword "blog."  By itself, it's very, very competitive.

Somehow Wordpress.com ranks #3 for blog.

They do not rank for "create a free website" which is in their homepage title but they do rank for "create a free blog" #1.

Their results are all over the place. They have a huge number of spammy, low quality subdomains. Are the inconsistencies because of the difficulty of these terms? Maybe. The spammy subdomains? Maybe.

But I can't see Wordpress.com ranking for "blog" if the subdomains could pull you down.

Take this for example (Just one LITTLE piece of the spammy pie):

http://bit.ly/1O5AzDr

[PatrickDelehanty]

Hi Amy

Good to know you're on top of everything! In short, yes, a subdomain can affect the performance of a root domain because a subdomain is ultimately part of the root domain. I just wanted to make sure you had your bases covered in the event you were putting all of your eggs into the subdomain basket.

If you don't mind me asking, why are there two subdomains that are eCommerce with duplicate content? From that standpoint, it sounds like only one subdomain is needed. Are the two subdomains...

https://parts.caps.com.au/
https://shop.caps.com.au/

And has traffic for those subdomains declined at the same rate as the root domain, if at all?

[paulissai]

Thank you so much for your response Patrick.

We have no manual actions on the main website and our MOZ spam score is 2/17. Our main website is full of original, good-quality content and we have been very careful to avoid any black hat seo strategies. We have had a professional seo expert audit our site and their feedback has been positive. In short, it seems like we have been doing everything right. We are mindful that the website might be affected by the current market for our industry, but have seen a very noticeable decline in our stats that seem to go beyond the usual market fluctuation backlash.

It is the two subdomains (e-commerce sites) that have duplicate content issues. I probably should have mentioned earlier that the decline coincided with the launch of the subdomains.

Keeping in mind that I am open to the possibility the cause of the decline could be isolated within the main website itself, I nevertheless would like to know if it is possible that subdomains can affect a root domain?

Thanks again for your detailed response - really appreciate it.

Amy

[PatrickDelehanty]

Hi Amy

Before assuming it is the subdomain that is the reason for your root domain's issues, I would take a look at your Webmaster Tools and analytics.

From the Webmaster Tools standpoint - login to Webmaster Tools (if you don't have it, you'll have to sign up - there is information on the site). Click the website you want to check (and the subdomains - if they don't have a WMT profile, set one up for each), goto "Search Traffic" under Dashboard on the left sidebar menu, and then click "Manual Actions". Make sure your site doesn't have any Site Wide or Partial Match Actions. If it does, there is your answer (at least part of it). You'll need to remove those penalties and also start making headway to make sure whatever caused those penalties won't happen again.

If you're not seeing anything there, for your analytics, note when the root domain started seeing declines in traffic and conversions from an organic traffic standpoint, and then I would check your keyword rankings to see what keywords and landing pages (you can also check landing pages in analytics) saw the biggest drop offs.

From there, you can line up this information with Moz's Algorithm Update Change History. Here, you can read about specific updates that have happened over time, a short description of what they affected, and links to resources for more information. Based on pages or keywords you saw drops in, you can line up against these algorithm changes and line up if it's a content, backlink profile, or another issue.

I would also have someone do an audit of your website to see if you are having fundamental SEO onsite/offsite issues, make sure redirects are properly in place if content moved, and also make sure your backlink profile isn't giving you any issues.

To me, without knowing anything about your site beyond what you have talked about here, it sounds like there are underlying issues that could be giving you trouble, not the subdomain. Especially since you are saying there were issues, including duplicate content - that sounds like a big reason there.

Let me know if this helps or if you need any more guidance on this - it could be a lot of things! Good luck!