> Do all source quizzes have an equal chance at being chosen to provide a question?
All questions meeting certain criteria are candidates for selection on any day. Criteria: qn must come from a quiz that is online, qn must be of above average difficulty as scored in quizzyland, qn must come from a quiz played at least X times, where X changes by category (higher in movies & music, lower in science, animals etc).
> Is the Daily Quiz reviewed by a human before being posted or is it all done by computer?
It is entirely automated. I can leave for a month and the daily game will run itself.
> Does all this take up much computer memory?
Nope, it's actually an incredibly brilliant system

The daily quiz is extremely lightweight on the system. It could easily support tens of thousands of players playing per day.
Terry