Besides Freelance Wrestling farming, the passive income system for Land owners seems to hinge on Fans (as far as I can tell). Game meta, especially post-alpha/beta, may prove me wrong... but given what we know from the big Land Utility guide, I am confident that Fans and Fan Quality are key concepts.
As a bonus, this is also my first 3Speak video! Hopefully I managed to navigate the frontend properly, heh.