Thank you for the kind comments - I'm trying to do my bit, there are plenty of us like yourself doing what we can.
Not so many thanks for asking me this question! :P
I believe transactions to be processed/completed (such as the 7 day life of an active post/comment) are in memory.
Completed transactions are stored on the HD/SSD of Full nodes.
Help, somoeone! @paulag @jackmiller