might be misunderstanding the term 'user space' and 'kernel space' but i think its refering to where the program/deamon resides in memory.
this is often refered to as user mode and kernel mode.
basically pretty much everything that you're going to launch yourself is gonna be user mode.
things that run in kernel mode will have direct access to your hardware and can do lots of naughty stuff if they were programmed to. when programming in assembly and you wanna write something in kernel mode ie some hardware IO operation then you need to preceed the instruction with an instruction saying hey i know what i'm doing let me get on with it.
anything that you want to run on your computer that requires a port to listen to or anything that changes the configuration of the kernel must be run in kernel mode. this doesn't mean that anything that then uses this newly opened port or whatever has to run in kernel mode.
basically the kernel acts as a go between for the user and the hardware so the user doesn't do anything silly that might break or crash the computer.
initd and crond and other such deamons run in kernel mode and are either started automatically at startup or have to be started by root.
x windows doesn't run in kernel mode. it has not real power over the operating system. theres nothing you can do in a window manager that you can't from the command line. its just an application to make your life easier.
(side point but MS windows runs its 'window manager' in kernel mode becuse the actual OS kernel is so intertwined with the 'window manager'. now whether your from a programming background or not its got to sound stupid that you link your steering wheel up to your engine.... i like that analogy.. might put that in my signiture.. anyway you don't want your car user to have the ability to tweak the engine using the steering wheel do you?)
hope this helped
not 100% on everything above and somones probably gonna slate me for being wrong but i think its a fair description if not a little convoluted