Multiple domain names

2 or more domain names pointing at the same site

[shuffler]

Hi all,

Scenario:
A website with a domain name such as companyname.co.uk is doing fairly well in the SEs with its main keyphrases. The company then purchase a new domain name such as prime-key-phrase.co.uk to point to the same website.

Question:
How could they begin to promote the new domain name, without damaging the rankings obtained on the other? Or even better, could they somehow transfer the work already invested onto the new domain name?

Thanks for anmy ideas

[IanTurner]

My view is that you would introduce the new site after a redesign of the old site. To ensure that there is enough difference between the two sites so the 'mirror' does not get thrown out of the listings.