I have 2 identical sites, only different is the banner, both are on completely different servers, one has the domain xyz.com and the other is xyz.co.uk My question is, Will G penalize me for this? Will one rank and the other one be given a duplicate content penalty. Does it even matter that they are on 2 different servers?
This is what happens from my experience: The 'best' one (first indexed/highest PR/most links) will rank, the other one won't. No penalties etc. just one being dropped. If the co.uk is hosted in the UK physically and the .com in the US/other then it might have effects on local searches but you can check that yourself.
One more tip: Don't ever bring the ranking of both the sites on the same level Bcoz if you do it then sometimes domain1.com's articles will be crawled first and somethign domain2.com's articles will be crawled first. this will result in down full of your main website.
Yep i agree, one site will get 'google washed' the other will fine. I often see this with duplicate pages on the same website. It would make sense to 301 one domain to the other, that way you can get the benefit of all the inbound links rather than splitting them across two sites. don't worry too much about ranking a .co.uk in the US results as long as you have backlinks from both countries then it should rank equally well in either country.