I think the course is great. After the initial excitement of getting my Pi up and running (to the point of doing a Google search) this little board has been sitting around on my desk for a few weeks gathering dust.
Finding out that the little LED labelled "OK" on the Pi's PCB is hooked up to the GPIO and can be turned on/off with a few lines of assembly language is exciting news!
Browsing through the pages of this online course... 10/10 to the author for an ace job at tutorial writing. You end up compiling to a new kernel.img that you copy over to the SD card. Plug it in, turn it on and it boots into your assembly. Somehow not as super-human feeling as directly controlling a 286 with Turbo Assembler back in the teenage years but certainly the most excited I've been in a long time.
My only prayer is that those pimply faced youths appreciate just how awesome it is to be controlling a piece of sand to make some gallium arsenide pump out bursts of photons are regular intervals.
The tutorial goes as far as describing and working with the message API to control the display driver. Gives a great overview of how the system works at a low level. Fantastic.