[simias]

I can think of one use for blockchains that can't easily be replicated otherwise (at least not with the same amount of security), it's proving that you knew something at some point in time. Putting something in the blockchain is like taking a picture of it with today's newspaper next to it so to speak, except you can't photoshop it.

If I made a groundbreaking discovery today, putting a sha-256 of it into the blockchain would be a very good proof later on that I actually owned it at this time.

But beyond that I agree with you. My (non-technical) girlfriend is looking into cryptocurrencies lately and she watches tons of youtube videos about it while doing her research (TEDx talks and the like). Easily 90% of the claims of "blockchain is going to revolutionize X" are easily dismissed either because the blockchain can't do what the person claims or there's an other, often simpler solution to this same issue. "Use the blockchain for food traceability", "use the blockchain to validate critical equipment firmware" etc... It sounds good as long as you don't think about it for more than 10 seconds.

The problem is that in order to realize that you need to have a rather deep technical knowledge about how the blockchain works, something 99% of people investing in crypto probably lack.

[acdha]

That still doesn’t require a full blockchain: 90s PGP with multiple signatures is all you need, or going really old school, mailing a copy to yourself using registered mail.

Imagine if a notary, post office, etc. set up a signing service: relational database, basic signatures for user-submitted hashes, etc. Not quite as good but much cheaper to run and much easier to have trusted by a court — I suspect most users would see no additional advantage by adding a blockchain.

[oarsinsync]

The change is in the trust model.

The centralised approach described requires that one trusts the database administrator. For a lot of things (probably the vast majority), this is good enough.

For the rest, there's decentralised distributed immutable ledgers.

[acdha]

Trust is an interesting topic: I think many people – and especially courts – would be actively disinclined to trust an anonymous blockchain but might be interested in one where it’s identified participants with reputations, liability, etc. Pay the USPS, Western Union, etc. and get a signature backed by insurance.

Trying to explain something like Bitcoin just seems like you’d have a hard time meeting reasonable doubt standards in a dispute but that’s not the only model.

[malmsteen]

Exactly, most people have done so for centuries. Of course with 99% reliability only, but no one cares about the 1% possibly added by blockchain (with a retarded additional computing burden to deal witg).

[bluecalm]

Publish a hash somewhere you can prove a date later, like a newspaper or w/e. Then if at any point you publish the text producing this hash you've just proven you had the text at the point of publishing the hash. Blockchain not needed.

[icebraining]

Or a letter to a fellow scientist:

In July of 1610 Galileo was still making discoveries faster than he could publish descriptions of them. On the 25th he discovered that Saturn was apparently situated between two smaller companions that always moved together. Wanting to establish his priority of discovery, but not yet ready to reveal what he had found, he sent to Kepler (and others) the following jumble of letters, which he informed them was a coded description of his latest discovery (...)

http://www.mathpages.com/home/kmath151/kmath151.htm