I've just designed a site for a client with 11 domain names who wants me to put exact copies of his site on each of them. Plus he wants me to register all of them to the engines. The sites are on different IPs, but they are all similar, except for the last number. (he purchased a sequential block of IP's)So the sites have all these things in common: IP address similarity, URL similarity, text matching, and the same link structure.
Now I'm very concerned, to say the least. My client insists that he wants all these in the search engines. Do ALL the search engines check for mirrors? What are the real consequences? Will the search engines just ignore mirrors, or will this cause the domains to be banned? Must I redesign all 11 sites, and have him find new hosts?
Are there are less complicated solutions?
Any help, or more information on the subject would be greatly appreciated.
It is so hard to run a mirror site. I generally promote the mirror site differently. Often I will do as little as change the template we use. For example, the main site [team-mp3.com], and its' mirror site [netins.net]. The content is the same, but the template is different. Both sites have been successfully indexed in search engines without the appearance of spam - (although the isp site always ranks higher).
That is the proto type we use when doing other mirrors. - always try to change something in both the html and the content. - often a something as little as printing the url of the page. - try to change filenames or path directory (I don't always do this).
If you make those little changes, the se can't determine it is a mirror site. Combined with the visual differences of a separate template, and it even looks like a different site should you be hand surfed by an se spam checker.
I used mirror sites (identical copies) on domains when I started out. I got burnt really quickly and started down the long road of trying to determine where the line is for search engines to regard specific pages as sufficiently dissimilar and therefore not penalise.
Excite was apalling at working out the duplicates. We managed to get multiple listings for good search terms (taking up the top 7 in 10 which had good & bad points). Gave me some breathing space regarding traffic whilst I was getting wacked by the other engines for listing dup. domains.
Depending on the size of your site, one route is to use each domain as a customized gateway in. Focus on specific unique content for each to back up your primary key words. This may be to much work from a maintenance point of view. Certainly in our case,the investment has been well worth it. :)