Thanks for the long answer!

I haven't heard of most of your abbreviations/term till now so I guess this will be one of the bigger journeys through the world of IT :)

I do have to say for the purpose of tinkering I love these bigger projects because you learn so much on the way. Now having read your answer I am even more exited to try it out :D

Are there any good recources on how to host you e-mail-server?

I guess slapping it on my local raspberry pi wouldn't be enough no? So you probably need a quite sophisticated setup so that there are no downtimes?

Yes and no. AFAIK when coding assembler for these chips you use CISC-instructions but they get translated into RISC-instructions by a hardcoded mikroprocessing-unit (not sure about the real term). So the processor itself gets RISC-instructions.