Registering multiple domain names is, and should be, common practice for businesses wishing to protect their brands. Once purchased, what you do with these domains can have a positive or negative impact on your main URL. Here are some tips on how to set up alternate domains to prevent the search engines from seeing duplicate content.
Domain Name Redirects
The first thing you need to consider after you've purchased additional domain names is to decide what you want to do with them. Not every domain name needs to have a site on it, though it wouldn't be a bad idea to have some kind of generic company page in place for lack of anything else. But for the most part, you will probably want to redirect all your alternate domain names to your main company site.
The question then becomes, how best to implement those redirects. There are many ways to redirect websites, most of them will often do more harm than good. One of the most common ways to redirect domain names is to "park" them and point them to your main site. How your web hosts parks domains is crucial to understand before implementing it, in order to make sure that the domains are redirecting properly from an SEO standpoint.
Here is an example of a improperly redirecting URL:

This is how most web host companies park domain names. Essentially, every parked domain will feed the user the content from the primary URL, but it keeps the visitor on the domain name which they typed in. This can lead to problems with branding, not to mention the duplicate page(s) created by this kind of re-direct.
Here's what you need to know about domain redirects. This is important so you are able to knowledgeably tell your web host, developer, or whoever else is in charge of your website. You want your alternate domains to "301 redirect" to your main URL.
A 301 redirect tells search engine spiders that the domain they tried to access has been "permanently moved" to a new location, which is your main URL. When implementing a 301 redirect both your visitors and search engine spiders will be automatically forwarded to the new URL.

If your web host doesn't implement this kind of redirect when parking domains or doesn't offer 301 redirecting, then you'll have to do it yourself. The easiest way is to get a second web hosting account for ONE of your alternate domain names, and implement the 301 redirect by adding the following code to your .htaccess file:
Redirect permanent / http://www.mainurl.com
Now you can park all your other alternate domain names onto the redirected domain.
Checking for proper redirects
If you're not sure if your alternate domain names are redirecting properly, you can do a simple check using a program such as WebBug.
This screenshot shows me that the domain www.projectinsight.com IS properly redirecting to www.projectinsight.net, returning an HTTP header of "301 Moved Permanently" which is exactly what we were looking to achieve.
Without implementing proper redirects on your alternate domain names, not only will you have duplicate websites, but you'll likely be splitting all your link flow between each version of the site. This will potentially cut your site's value (as determined by the search engines via incoming links) in half.
While it's possible for the search engines to figure out that domain A and domain B are the same, you're still forcing them to decide which of the two domains is the one you are trying to brand, and they have a 50% or greater chance of getting it wrong.
This article is a continuation in my series on duplicate content. Follow the links below to read more:

Great article stoney, it also might be beneficial for you to redirect your http://yourname.com to http://www.yourname.com (or the other way around)... i heard duplicate content penalties can also result from this (although you would think google would be smart enough to realize that they are the same site)
Thanks James. You're absolutely right. Funny, that was actually going to be my post for today but Scott beat me to it .
Stoney,
Fantastic article, really helped me to get a grasp on an issue I had been dealing with lately. It *literally* came at just the right time, too!
Keep up the great work.
Stoney,
What about 301 redirects and using this alternate domain names for ppc for Google AdWords. Would this be a problem with redirects and AdWords? People use these alternate pointed domain names for a new display URL in their ads to attract more targeted visitors and to increase the quality score of the ppc ad to the landing page URL?
Why is there even an option to have a permanent redirect or a temporary redirect? In what instance would it be beneficial to use a temporary redirect?
I have 5 web sites, and want to construct a web portal which will unify all sites in one (on new location, same IP) with new unique content. After this (constructing a new portal) want to redirect all this domains (301 redirection), to new one, we presume that this will not affect our position on Google, is it possible for us that Google bann us from index, because of redirecting 5 domains to one? I know that 301 is a legal, but I found different opinions, like
“If you 301 several different domains/web pages to ONE single page,
that ONE single page will get humped and dumped by google with no
apologies. DONT DO IT!
If you're already getting traffic from google, I would caution against
doing anything at all! If you do anything wrong with regards to
301/302/404, google will break it off in your culo and drop you so far
in the rankings that you will soon be on welfare.”
So if You be so kind to help I would appreciate.
I've never heard of Google dumping a site because they 301d too many sites to one location. I could see this happening if you 301 redirected five sites and each essentially redirected to the exact same pages, but not if they are redirecting each site to different pages.
My questions then are this:
Does each site currently have unique content? If so, is the exact same content going to be placed on the new site?
If they answer is yes, they I doubt you'll have any problems, but you still might want to play it a bit cautiously. I suggest 301 redirecting one site at a time. Don't put the content up on the *new* site until you're ready to implement the page to page redirects. Let a month or more lag between redirecting each site.
This will do a couple of things, the search engines will see new content being added to your new site spread out over time. This can be good. But it also eliminates any potential issue if they see a bunch of redirected sites all at once.
Also, it'll ensure that you don't see a sudden traffic drop from all your sites. Whenever you implement your 301 redirects you'll see rankings drop almost completely. It'll take a few months to see them start coming back. Spreading out the redirects will allow you to keep rankings on four sites until the rankings for the most recently redirected start to return.
It'll be slow going but you might find it beneficial to do it this way, especially if you depend on web traffic for your livelihood.
Hope this helps.
BingoBob, Good question, I've often wondered that myself.
There are situations where things have to be moved around but they are only temporary changes. Those are the instances you would use a 302 redirect. 301 redirects pass page /link value while the 302 does not. If you imlplement a 301 you'll see SERPS change with the new page in question. Using a 302 you will still see the URL of the old page but clicking it will take you to the new page.
Another thing to note is that the 302 has a more immediate effect. With a 301, the search engines will essentially drop the old page out of the rankings, then respider the new page. Rankings on 301 redirects are often lost for a month or more. That usually won't happen with a 302.
Some use a 302 redirect for about six months or so then change them to a 301. This will help keep pages from dropping out of the index while the search engines spider the new page. Once it's in the index for a few months then you can change the 302 to a 301. This can prevent ranking downtime of just using the 301.
Great post on a much needed basic reminder :-)
Maria Reyes-McDavis
Now one gets to wondering, if one has 50,000 unused domains in a marketplace, seeing on average 1 type-in visitor per day per site, and redirects them all to one destination site in said marketplace, is that 50,000 unique, targeted vistors per day, sans any search engine exposure, for an overhead cost of $400,000 per year? In other words, 18,250,000 targeted visitors/year from direct traffic for $400k, which is then reduced by the (appreciating?) asset value of those 50,000 domains?
It's the new math, and those are conservative numbers. Of course I kid... nobody does that. It would be crazy, require so much management, etc etc etc.
dfas
Opps! Sorry guys, I accidentally hit the return key. Nice article Stoney! Good Job. Lenito
I plat to put IP under each directory for example:
www.something.com/one/index.php one IP
www.something.com/two/index.php other IP, etc. I plan to have new portal and 5 sites parallel and at the beginning I will redirect only one (just to see what will happend), content will be different (because of crawlers), and every two months I’ll redirect one site if all goes well. Because I find this topic important here are answer from one other forum that I found very good, so tell me what you are thinking.
That's an interesting question, thanks for bringing it up. In general,
the best practice for migrating multiple sites into a single one is
very similar to moving from one domain to another:
1. Make sure that the new site structure and the code can be crawled
easily and complies with our Webmaster Guidelines (
http://www.google.com/support/webmasters/bin/answer.py?answer=35769 ).
Sometimes that's easier said than done :-), especially when the new
site is supposed to use some neat new system that really looks nice
but acts more like a wall between the content and search engine
crawlers (and often users).
2. 301 redirect all old URLs to the appropriate new ones. It's
important that you do this on a page-by-page basis so that visitors
wanting to visit the old page about say the hotel's fitness facilities
actually arrive at that page on the new domain (search engine crawlers
appreciate this as well). In comparison, redirecting all of the old
pages to the main hotel-group homepage would be confusing to visitors
(and crawlers). If your new website has a completely different
structure for each hotel, it would be good to get each URL redirected
to the best matching new URL. Depending on the magnitude of your move
and structure change, that can be a lot of work, but visitors and
search engine crawlers will thank you for your effort!
3. Contact webmasters who have linked to the old sites and ask them to
change their links wherever possible. If you are doing a complete make-
over of the site, why not mention that as well :-). You can find a
fairly comprehensive sample of your links in our Webmaster Tools, if
you have verified ownership of the old domain names.
4. Verify that your own pages are all linking properly. Confirm each
redirect if you can, especially if your old site was using a CMS with
dynamic URL parameters. Make sure that none of your new pages are
linking to the old ones. You can check these links (and to some extent
crawlability in general) with Xenu's link sleuth (
http://home.snafu.de/tilman/xenulink.html ), a freeware tool for
Windows.
5. Monitor your progress and keep an eye open for errors. Make sure
you have these sites listed in your Webmaster Tools account and watch
out for any errors that may be shown there.
Some additional ideas that you may with to integrate in your move:
- Start with one site and incrementally add the others once you see
that the moved URLs are being crawled and indexed as you would like.
- Create and maintain an XML Sitemap file for your new site. Depending
on your CMS, this may be as easy as clicking the right button :-).
- Inform you existing customers of your move and/or change in branding
and ask them for feedback. After all, what good is a nicely indexed
website if your customers aren't happy with it?
In general, provided you follow steps like the above, there would
generally be no reason for us to discredit your new website. After
all, it is very likely the logical successor to your existing sites
and if it provides the same (or more!) value to your visitors, there's
no reason for us to treat it any differently.
Good luck with your move!
And sorry Stoney, yes each site have unique content (if you want I'll send you links), but again I plan to put a similar but diferent content on portal, which must unifie whole offer. And thanks for the answer, I found it very informativ.
"What about 301 redirects and using this alternate domain names for ppc for Google AdWords. Would this be a problem with redirects and AdWords? People use these alternate pointed domain names for a new display URL in their ads to attract more targeted visitors and to increase the quality score of the ppc ad to the landing page URL?"
Jennie, I'm sorry, I didn't see your comment earlier. I don't thin that Google will allow you to do those redirects, but I could be mistaken. Last time we tried something like that we had a domain that 301 redirected, used the redirected domain in the ad and Google pulled it because of that. If you want to do something like that then I suggest building a one page site on that domain (keep spiders out by using robots.txt) and then forcing the visitor to the new site once they decide to click anywhere.
Zelko, I can't for the life of me think of a reason why you would one website to use several different IP addresses. I think that's completely opposite of what you would want to do. Unless there is a more technical reason that I'm not aware of.
I also think that the text from the old redirecting site should be as identical as possible to the new version. I know that's not always feasible, with a new site comes altered text, but this will help the redirects go more smoothly overall.
Yes but I read that if I have a identical (or even similar) content on to places, Google will penalize that, so what You suggest after all? Few IP-s because I want Google to think that under each IP is one site (in fact that the true but on one place, under one portal), so instead of www.something.com IP will point to www.newportal.com/something/, am I clear enough.
I though that you were redirecting form old to new. In that case the old content shouldn't be available to the search engines.
Of course if you mean that by redirecting one old site at a time, but having the new content for all the sites on the new site, then I see your point. My recommendation would be not to have ALL the new content on the new site. Only make that content available when you're ready to implement the next redirect.
Regarding the IP differences. I think it just appears fishy without any positive gain. Which means there is only a downside with no upside. Unless I don't see the upside.

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