Does a subdomain penalty affect the main domain?

Let's say i have a realtor website doing ok in the search, having a DA/PA of 50. I then create a subdomain like keyword.realtor.com and spam the hell out of it. The subdomain eventually gets penalized. Will this penalty affect the domain in any way?

It shouldn't, but things change fast, it may depend on your reputation.
Imagine what happens with free subdomain page hosters.

Never heard of it hurting but there is link structure involved.


Direct from G

"Google has said that it will be more likely to treat subdomains as if they are subdirectories of their parent domains unless the subdomains demonstrate they are offering sufficient unique value independently of the root domains"

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WebProm said:

It shouldn't, but things change fast, it may depend on your reputation.
Imagine what happens with free subdomain page hosters.

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That's what i was thinking myself, i mean right now i know for a fact that google treats subdomains as separate domains or at least that's what they claim...

fxphil said:

Never heard of it hurting but there is link structure involved.


Direct from G

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the quote from G complicates things a lot...

Lol complicates things? IT acts as subfolders for related information but if it's not related it acts as a separate domain. Look at Tumblr

alvin.orrt said:

That's what i was thinking myself, i mean right now i know for a fact that google treats subdomains as separate domains or at least that's what they claim...



the quote from G complicates things a lot...

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My experience: In the past (about year ago) I had deindexed subdomain, while the main domain has not SERP/PR changes.
Who knows today. I see many subdomains on web platforms like wix and weebly ranked in top 10, but tumblr is almost invisible now. There have huge pagerank drop in xanga (0 from 6).

so google sais: "Google has said that it will be more likely to treat subdomains as if they are subdirectories of their parent domains unless the subdomains demonstrate they are offering sufficient unique value independently of the root domains"

what i understand from this is that if the website on the subdomain is just a landing page targeting the same keywords as the root domain - then it does not offer sufficient unique value so they will be treated as subdirectories - so without sufficient unique value keyword.realtor.com would be treated as realtor.com/keyword - and i think that would penalize the root domain.

and tumblr and wordpress and others, they're about creating your website and blogging - the actual subdomains / sites on tumblr and wp are about all kinds of things but not about creating a site.

anyway, i like where this discussion is going, looking forward to hearing more opinions

naskootbg said:

My experience: In the past (about year ago) I had deindexed subdomain, while the main domain has not SERP/PR changes.
Who knows today. I see many subdomains on web platforms like wix and weebly ranked in top 10, but tumblr is almost invisible now. There have huge pagerank drop in xanga (0 from 6).

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Thanks for the input, it's good to hear that your main domain was ok.

it's pretty normal for big websites to be safe if the subdomains get penalized but i want to know what happens to smaller websites, PR3 and less

what i understand from this is that if the website on the subdomain is just a landing page targeting the same keywords as the root domain - then it does not offer sufficient unique value so they will be treated as subdirectories - so without sufficient unique value keyword.realtor.com would be treated as realtor.com/keyword - and i think that would penalize the root domain.

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MY question to you would be why not Deindex the landing/money page but the create seprate folders for each keyword.

What this will do is not penalize your money site because it's not indexed but it will still allow you to drive people to it from the subfolders.

No, they should be treated as completely separate domains. Otherwise every wordpress or blogspot subdomain would be screwed. Links built to one subdomain only effect the rankings (be that positively or negatively) of that specific subdomain

fxphil said:

MY question to you would be why not Deindex the landing/money page but the create seprate folders for each keyword.

What this will do is not penalize your money site because it's not indexed but it will still allow you to drive people to it from the subfolders.

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I don't get it Phil, please explain in more detail...
I have a website which is ranking decent for some realtor keywords - competition is pretty big and i have a great link profile which i don't want to ruin by building crappy links.
So my idea was to create a subdomain which i could then blast with tons of spammy links so i could rank in the top 5 and if it eventually fails the main website wouldn't get penalized. On the subdomain, i would then have just a landing page - so in the eyes of google, not sufficient unique value.

And there's one more thing - let's say i have a page on my website, realtor.com/keyword - if i spam the hell out of this page, would the penalty extend throughout the site?