Forum Moderators: phranque
Here is the long version:
This is what happened and my current situation:
I really wanted to have DomainB.com however it was owned by someone else (and was expiring soon but that was different story). So I came up with different name for my site and got DomainA.com. I put up robots.txt file to disallow any bot, and started some preliminary development, however no links on the hope page). Month and a half later I checked availability for DomainB.com (one I wanted), and since it was available I got it. Itransfered all the work to it and continued development. My hosting service allows me to host multiple domains on the same account. I am on the shared hosting, and my hosting service changed my settings such that domainB is my main account, and domainA is a sub-folder in my pblic_html (however still it’s “own” domain – when I type in it’s URL it points me to it). My question about two domains having the same IP was prompted when I checked google for DomainA (old one). Google knows about it and it just has a link to the home page. I tried the same for DomainB (one I like) and nothing – I am not sure if here is a issue because of the IP, or it’s just a matter of time before Ses learn about second domain and treat it as a separate entity. (uhhhh, long post).
Thanks a lot
1) Duplicate content
This applies to any setup where two or more domains come into play, regardless whether it is single-IP or not. if www.example.com and www.example.co.uk show the exact same content (because they are for example both a virtual server sharing the same directory) then you run danger of getting a duplicate content penalty.
The solution to this is to decide for ONE domain as being the one-and-only, and to set up permanent redirects (often called 301 redirects) from the second domain.
2) Heavy interlinking
If two domains on the same IP do heavy interlinking (like EVERY page in site-2 links to the front page of site-1), then those links are most likely discounted in the ranking equation. In the eyes of the search engines this smells like pretty dumb linkfarming, and is devalued in the best case scenario. In the worst case scenario it is penalized.
I personally run about 10 sites on the same IP. They are all thematically related but have unique content of their own. There is slight interlinking among these sites. Every single one of them ranks great for their important keywords, and for some keywords you even see 2 or sometimes 3 of my sites (from the same IP) being on the same result page.