Just as a reminder: The original stated task was to protect against "untrusted intermediaries" and "patchy network connections", and in particular to make "sure that the *intermediaries* haven't added, changed or removed any posts in the feed." … which can perfectly well be done with simple signed, timestamped, indexed posts and having the reading client app check the signature and post indices.
In contrast, this here, which is the only thing the blockchain struckture really adds:
> The signer (malicious or not) can resign an old message & effectively overwrite a previous message
… is a rather radical shift of the goalpost, as the only capability the blockchain really adds is to protect against modification not by untrusted intermediaries (which was the purpose and which would already be covered without a blockchain) but by the legitimate owner/editor of the feed.
In other words: The only thing the blockchain adds is that it makes it impossible for YOU as the user to edit YOUR OWN posts. I'm not sure that's something most people in the social network context (as opposed to, say, a financial transaction ledger) would see as a feature and not an anti-feature.
In contrast, this here, which is the only thing the blockchain struckture really adds:
> The signer (malicious or not) can resign an old message & effectively overwrite a previous message
… is a rather radical shift of the goalpost, as the only capability the blockchain really adds is to protect against modification not by untrusted intermediaries (which was the purpose and which would already be covered without a blockchain) but by the legitimate owner/editor of the feed.
In other words: The only thing the blockchain adds is that it makes it impossible for YOU as the user to edit YOUR OWN posts. I'm not sure that's something most people in the social network context (as opposed to, say, a financial transaction ledger) would see as a feature and not an anti-feature.