This post will be a little longer, but I will appreciate any feedback greatly...

Currently I operate a site hosted by Yahoo Stores with plans to move out within the next 4-6 months. As we speak, the new shopping cart platform is ~75% complete. When it is finished, I plan to soft launch the new platform at another domain name, say "bluewidgets.com", instead of replacing the one now, "redwidgets.com".

My main concerns are SEO related, as 40% of our traffic comes through SEs. We rank very well in keywords related to our core products at "redwidgets.com" on Google, MSN, and Yahoo (though not as well as the other two). What will happen when I soft launch "bluewidgets.com" and have these two sites co-exist?

Different:
- domain name
- store name (thus changing links for products)
- site structure and layout

Same:
- site content (most importantly, products details such as description, names, item code, etc.)

How much will have duplicated content on both these domains hurt my rankings at "redwidgets.com"?

This is a big concern because after thorough testing of "bluewidgets.com", I plan to use the new platform at "redwidgets.com", where all my high ranking keywords currently resides.

Any feedback is greatly appreciated, thanks!!!

duplicate content will hurt... but make different meta data...

Thanks for the reply.

As far as I was aware, I thought duplicated content would be harmful only when it came to content within the same website.

Anyone with comments or suggestions regarding soft launch?

duplicate content..... it does not matter if it is on your site or at another site... it gets penalties.

You're going to take some sort of a hit on this, really no matter what you do. You're launching a new domain, so all the sweat equity you have built in the old one is lost.

Your very best bet to make this succeed is to keep the same domain and pull the switch all at once, being sure you have in redirects in place from the old site structure URLs to the new.

Barring that, as soon as you deactivate the redwidgets domain at Yahoo Stores, set it up on its own hosting. You don't need any content here, simply the redirects from the old to new site structures.

The first way you'll take somewhat of a it for a while, but should then start seeing steady recovery. The second method is a bit more iffy as, again, you're working with what the SEs will consider a new site.

Hmmm, maybe I misunderstood what you want to do as I just reread this:
I plan to use the new platform at "redwidgets.com", where all my high ranking keywords currently resides.
If the ultimate destination is still going to be redwidgets, then I really don't see a problem. If bluewidgets is just going to be used for testing, simply block access to it from all but your testing IPs. Then pull the redwidgets to redwidgets switch as above.

>to make this succeed is to keep the same domain and pull the switch all at once, being sure you have in redirects in place from the old site structure URLs to the new

I agree except to say that with a Yahoo store it may not be possible to do proper redirects. If someone knows how to do this please share.

If he keeps the same domain the redirects would be set up on is new hosting.

Yes that would work, if the Yahoo store site is moved to another host first, and every page retains is former name after the move.