Will having duplicate domains hurt?

At lunarpages if you park a domain, you can point it to one of your accounts and it basically just dupes it but changes the domain to the new one running off the originals folder. You can do sort of the same thing by just pointing your new domain to a folder of a site you own and want to dupe.

Will this hurt my original sites google ranking? Cant hurt it now as it is still a 0, but I just mean over all, preventing it from ever moving up the page ranks.

Thanls

It can if there the exact same. Why mess with it. Just set up your domain if you plan on using it.