Alot of the content within the community sites are all interconnected, meaning, alot of the content is shared between all the sites, but if you look through the different categories, you will notice that there is alot of stuff that will be exclusive to the linuxmint-art.org site, things like wallpapers, GDMs, KDMs, bootspashes, icons, logos, etc. will only be on the linuxmint-art.org site. GTK and QT themes are shared between all the sites.
I don't belive ppl would see it as a copy, and this is the reason. The *-look.org, and *-art.org sites, are all hosted by the same server, opendesktop.org, and you pretty much have to be invited into the community, to get one these community sites. And that also means that this is not an independent site, it is part of the opendesktop.org community, as the first post in this announcement states, we have joined the community, and made our own community that much larger. The CMS (content management system) used in all of these sites is written, and maintained by Frank, the creator of the entire od.org community. I contacted him asking about the CMS he uses, and he took a look at our community, and then informed me that the whole system is custom written by him, but he offered us a community site within od.org, which in my opinion. is a great honor, as this is one the biggest opensource communities on the web. This is going to bring Mint up to the level of Debian, Gentoo, Suse, and all the other huge name distros, and really help to further the Mint OS, and community as a whole.
I can see where one may confused, not everyone knows that these sites are all part of one large community host. But just being a part of the community, makes ppl take a closer look at the distro, and become more interested in it, because it is put into the same level of respect as all the other big distros, and also to the level of Gnome, KDE, XFCE etc. So I believe that this really is something huge for Mint, not just a web site, but a way to further everything that everyone has worked so hard for.