I’m baffled so many are proposing “solutions” which only make the governance experience clunkier and more centralized: increase rejection cost, timeout neurons if a proposal is rejected, limit proposals to named neurons, etc…
I’d understand if there were no other way, but much better and more holistic solutions have already been proposed, @skilesare’s ReProposal: Spam Prevention - Convert from system-based rewards to voter based rewards and @wpb’s Periodic Confirmation of Neuron Followees eliminate the spam’s financial incentives, so the only problem left to be solved is advertisement and malicious content being posted on the NNS, which would be fixed by adding a “spam” button as a voting option, many other DAOs use the same solution, e.g on Cosmos you can: accept, reject, abstain or report spam (called No with veto). Implement these 3 features and you have a much better NNS experience than with anything proposed in this thread.