If we have multiple domain having same content, then how to work on these website as here duplicate content occurs
If you keep same content in your different domains, there is high chance to get penalized! There is a trick for that, You can use "iframe" in your HTML page, Sol could crawlers can't see the duplicate content.
This isn't black hat as iframes have no SEO potential. This means google cant read the iframe so the page won't rank very well. Keep the actual content on your best ranking site and put that page in an iframe on the other sites.
NEVER use the same content for multiple websites. It won't do you any good. Write different content for all your websites or use Article Spinning. I would recommend setting up a different niche site than setting up the same site over again.
I know the latest buzz is all about duplicate content and what not, but personally I find this very hard to believe. I've been hearing about a duplicate content penalty for quite a long time now, pretty much since the advent of autoblogs, but to this day I haven't run into any difficulties. There are TONS of very large powerful websites which are solely based on duplicate content, they're called news aggregators... Google LOVES these sites and I just don't see it as becoming a bad thing, perhaps you might want to reference your source with a backlink, but I wouldn't worry about it so much.
You have to create unique content to the different domains. otherwise Google will banned you for duplicate content
Always use unique content..If your site has duplicate content..may be its get banned by search robots..So always use fresh content