Fundamentally, a struggle between asshats and honest users/admins is a struggle of attrition. The honest participants only win the struggle if they can make it

Fundamentally, a struggle between asshats and honest users/admins is a struggle of attrition. The honest participants only win the struggle if they can make it too costly for asshats to continue participating. To achieve this, it would be sufficient to make it so the cost of registering a user account is asymptotically more expensive than the cost of shadowbanning an account. If the software required that each additional account a user registers costs more in USD terms than the previous account, while keeping the cost of shadowbanning a username constant, then the honest participants will win in a struggle against asshats who must keep registering accounts to circumvent the shadowban. A strawman approach would be to require all user accounts to be tied to real-world identities. Then, the software can track how many accounts a real-world person has registered, and bill them accordingly. This obviously has other unrelated problems, but it does make it possible to penalize asshats more and more harshly for each infraction. I was suggesting that a blockchain could be a useful building block here, since it already exists, is widely deployed, and costs money to write state. A more practical approach than the strawman could be to implement a username registration system on a blockchain, such that each registrant must burn some of the blockchain's tokens to register a username (thereby imposing a cost to doing so). Crucially, the number of tokens burnt per name would increase as more and more usernames get registered (or as more and more time passes), and in doing so make it more and more costly for asshats to circumvent a shadowban. This would also make it so asshats would lose a war of attrition against admins, and could be implemented today.