domain.com and www.domain.com, google sees it as duplicate content..

[pbracc]

Is it true that domain.com and www.domain.com is seen by google as duplicate content and especially after the last algo updates it's become one of the things that penalized many sites?
Ive searched on google for "porn", the first 7 results (pornhub, youporn, etc.) do have in facts a redirect from no www to www.domain.
The others on the first page (like xhamster, elephanttube) dont. I see that all the first ones have it but the others are still on first page without it.

Any knowledge to share?
Thanks

[DamageX]

Historically that has been the case. Nowadays, however, Google has gotten better at identifying the two as the same. That being said, the best way to prevent a fuckup on Google's part is to do a 301 redirect from the www version to the non-www version, or vice-versa. Your host should be able to help you with this, if you don't know how or are unable to do it.

[arock]

I wouldnt worry about it, vast majority of sites dont redirect to .www

[faxxaff]

No need to worry about that anymore. Google is able to figure that out.
It was used to be a problem until 2009 or so when you had incoming links to different www or non-www version where you were bleeding authority and rank over 2 pages. In such case a simple redirect code like ADX said, would be useful.

[Thumb Angels]

RewriteEngine on
RewriteCond %{HTTP_HOST} !^(www\.|$) [NC]
RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

Here is the code if anyone needs it

[bud]

Use Webmaster Tools to tell us how you prefer your site to be indexed: You can tell Google your preferred domain (for example, http://www.example.com or http://example.com).

http://support.google.com/webmasters...n&answer=66359

[JACOBKELL]

Use Webmaster Tools to tell us how you prefer your site to be indexed: You can tell Google your preferred domain (for example, http://www.example.com or http://example.com).

http://support.google.com/webmasters...n&answer=66359

Yes that is key,301 redirect is not even needed.But problem after you do that google will not update for years your preferred way on serps

[pbracc]

Thanks guys, ive added it just to one site out of curiosity to see if anything changes.
Ive used a code slightly different from the one used by thumbangels tho:

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www.domain.com$ [NC]
RewriteRule ^(.*)$ http://www.domain.com/$1 [L,R=301]

[CraK]

Use Webmaster Tools to tell us how you prefer your site to be indexed: You can tell Google your preferred domain (for example, http://www.example.com or http://example.com).

http://support.google.com/webmasters...n&answer=66359

This is how I currently tell Google what it should be prioritizing.

[notluxv]

I also notice that in Webmaster tools, it will tell me I have duplicate content for trailing slash and non-slash urls.
/tag/blowjob
/tag/blowjob/

I don't know how much of an issue it is but I put a rel=canonical meta tag on the one I preferred to be on the safe side.

[DamageX]

Use Webmaster Tools to tell us how you prefer your site to be indexed: You can tell Google your preferred domain (for example, http://www.example.com or http://example.com).

http://support.google.com/webmasters...n&answer=66359

Using ANY Google tool = telling Google more than it needs to know about your business.

[notluxv]

Using ANY Google tool = telling Google more than it needs to know about your business.

That's true but some things I think I want Google to know about my site. For example I have a site that gets a good amount of type-in traffic and I'd think that would be beneficial and something they wouldn't know otherwise.

[JACOBKELL]

That's true but some things I think I want Google to know about my site. For example I have a site that gets a good amount of type-in traffic and I'd think that would be beneficial and something they wouldn't know otherwise.

I was starting to think same lately,will see will that work or backfire

[Dred]

Why choose just one or the the other?

I use this in my .htaccess:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.domainname\.com
RewriteRule ^(.*)$ http://domainname.com/$1 [R=permanent,L]

as well as setting it to non-www in Google Webmaster Tools.

I figure it couldn't hurt to use both .htaccess AND Google WebmasterTools to cover my ass.

I even hit up Bepe to update my ST license keys to be non-www as I build sites. I don't launch my MGPs until that change has been made (well, not until I update the license key and domain key in my ST admin after he's changed them).