Tell me about public blockchain apps that do not involve objective money or objective identity, which require strict global consensus, why they should be built on public blockchains, and why haven't they been built yet? I'll consider writing a post, when I get back to it, to explain why it does or doesn't make sense

- every ai generator (image, video) to attest that an output was altered with or created by ai. Every social media platform that gets that output shared to be able to flag it as such. Reduces deepfake issues and introduces authenticated media