• GNOME = Ubuntu Desktop Edition
• KDE = Kubuntu Desktop Edition
• Unity = Ubuntu Netbook Edition (Lucid/Maverick+) & Ubuntu Light
• UNR = Ubuntu Netbook Remix (<=Karmic)
• Plasma-netbook = Kubuntu Netbook Remix
• Foundations = kernels/X11/toolchain/linaro
• Server = redirect to serverfault.com ? Unless it's about byobu or setting up deb mirrors/proxies
• branding = "How do I get back to [x|k|studio]ubuntu wallpaper/login screen/plymouth"

The idea is that "Ubuntu Desktop" question will most likely be about GNOME/GUI apps & desktop environment. Similarly "Kubuntu" question would want an answer for KDE/Qt apps. Similarly netbook-remix'y should only deal with those customised UI's instead of general app questions.