Pro-Tip: Raspbian comes with loads of bloatware. If you really need a headless server go ahead and install Ubuntu Server 14.04... IMO much better than Snappy Ubuntu Core
Ubuntu Snappy Core does not work on Raspberry Pi Zero, or for that matter on any ARMv6, such as most RPi models: 0,A,A+,B and B+. All of above are based on BCM2835/BCM2708 SoC.
UbuntuSC requires ARMv7 ISA CPU, which among Raspberry Pi models is only featured on the BCM2836/BCM2709 SoC in "Rasbperry Pi 2 Model B" (note the "2").
This distro was just added a couple weeks ago, and is the same as Raspbian, but without all the GUI bits, apps like Minecraft and Wolfram, and it boots to the console without automatic login.
I used to use 'Diet Raspbian,' which took plain Raspbian and stripped it down, but this is a much nicer alternative, since it's an official build!
I tried Snappy and won't use it again. to enable wifi involves manually installing dpkgs, rather than using the snappy package system. that's a regression from ubuntu.
Good tip. Also, there are options that can be built from source (e.g., BSD) so that all that cruft is not installed by default. IME, 8 GB SD cards are not needed; 1 GB and smaller can suffice.
UbuntuSC requires ARMv7 ISA CPU, which among Raspberry Pi models is only featured on the BCM2836/BCM2709 SoC in "Rasbperry Pi 2 Model B" (note the "2").