Two domain names for same site

Duplicate content penalty?

[molsen]

If a site has two domain names pointing to the same site, will Google penalize one (or both?) for duplicate content? Would using a perm redirect help prevent this?

[GordonS]

I would definitely like to know the answer to this. It's common to change a brand by running the same content under two domain names for a period. We did the same thing and we "feel" that we were penalised by Google for a very long time for so doing due to duplicate content.

[Terabytes]

duplicate content...

Here is a true-life scenario...

I originally wanted a specific ".com" domain name however it was not available. I purchased the ".net" variety and began to build a web site, waiting for the ".com" to become avalable...

During this time I knew nothing about search engine submissions so the site went un-submitted...(8 years ago)

(there is a point to all this...bear with me...) 8-)

All of the back end web issues were handled by the ".net" domain (mail, forms, etc).

I purchased the ".com" domain when it became available, and configured it to point to my current (.net)web site. By this time I was starting to submit my site to everywhere...I decided that the ".com" was what I really wanted and began to submit it...

so far...everything is great...my listings are happening....(I'm on my way to fame and fortune...lol).

My Error: hardcoding a link to my forms so that they were always sent users to the ".net" domain..(my forms only worked if they were submitted from my original ".net" domain name...)(this is before I knew about mods and such)

The Point: When I get indexed as ".com" the SE located my internal link to my form page in the ".net" domain, and began to index the ".net" web site along with the ".com" site...IDENTICAL CONTENT....

My current situation, is as follows:

Google shows ".com" results...If I search for ".net" I show a result....but only if I look for it...Google decided duplicate content fell on the ".com" side...and only shows ".com" results...

Yahoo shows ".net" results...likewise on the search for ".com"..but only diplays ".net" for searches..Yahoo decided that duplicate content fell on the ".net" side

It's deffinately something to consider when linking the 2 or more domain names together. You may not achieve what you're looking for, and you may just kill one of the domains...and you won't have a choice as to which domain gets dropped...

duplicate content from different domain names, kills 1 or more of the domains listings....

Just my 2-cents...

[webdude]

I have a site that has well over 20 domain names pointed to it. The trick is to 301 to just one domain. To do this, set up your dns for 2 sites and create a dummy site.

Lets say you have...

site1.com
site2.com
site3.com

Of course then you have...

www.site1.com
www.site2.com
www.site3.com

Let's say you want www.site1.com as your main site. On the server, set up a dummy site and point everything to it via dns except for www.site1.com. Set up another dns record to point to www.site1.com. Then do a 301 for all those other sites to go to www.site1.com.

Got me out of trouble.

Is this making sense?