Blockchain-based social media isn't new, so what makes this special?

Is there a technical write up where we can see how consensus works and what guarantees you have that the chain history can't be rewritten?

A social media where posts are permanent. Edits are guarded against via cryptographic signature. Deletes are guarded against via chaining. I think, with identity verification, permanence massively increases the quality of discourse. Such identity verification will become necessary soon for everyone due to AI fraud, but at any rate, I think this app would be very useful to hold public figures to their words.