I've been told contradicting things and would like to know what the facts are. As I'm sure many of you know, Domain Aliases (www.domain.net aliasing to www.domain.com) are very common across the net. This especially true when working with a specific branding point where you own domain.com, .net, .org, and various other versions of the domain names involved. So, the question I have is how does google treat these? Are they considered duplicate content and is there the risk of Penalty for these?