Alias Domains - Is this Mirroring?

[curly_clare]

hello,

I've just seen a site in the SERP's that has two alias's. One is a .co.uk version and the other a .com version. The sites are identical and use the same pages from the same server.

Is this classed as mirroring, taking into consideration that both domians are indexed in a SE's?

If it is, wouldn't it be better to employ a 301 permanent redirect from the .com site to the .co.uk site?

Just interested in what you guys think!

[delboy1978uk]

a mirror site is the same content on a different server
what these guys have done is just bought some domains and redirected the index file to wherever their site is being hosted