I aware that many social media platforms based on blockchain has similar problem, such as plagiarism and spammers.
Why? Because that's really easy to exist in blockchain social media platforms. No centralization power in blockchain platform. Easier to earn money by manipulate certain cryptocurrency system with using the weakness of certain blockchain system and nepotism among users.
So how to minimize plagiarism and spammers? It's depending on founder, user witness or miner itself. If we want to feel the land of freedom (I think it's quite anarchy), try to be active on many social media platforms based on blockchain and cryptocurrency. You will be know about soon how the wild of blockchain and cryptocurrency world.
Be careful in this world because many pirates still sailing on the ocean of social media platforms based on blockchain and cryptocurrency.