[atweiden]

> or can be coordinated by users in the network

Phone-a-friend consensus aka “weak subjectivity” doesn’t meaningfully differ from the administration of centralized Git repositories. If your blockchain requires human intervention to resolve disputes, as do all pure proof of stake implementations, you probably never needed a blockchain to begin with.

[iownzerobtc]

All blockchains require social coordination. How do you think Bitcoin operates? A protocol is developed and some facet of society decides to build a client to support that. Somebody adds a new BIP and the network of users may decide to coordinate in order to upgraded the protocol (soft or hard fork).

[atweiden]

> All blockchains require social coordination. How do you think Bitcoin operates?

That’s a great question, and one Jude C. Nelson — who has a PhD in distributed systems from Princeton — is better equipped to answer [1] than me (or you, probably):

“PoW requires less proactive trust and coordination between community members than PoS -- and thus is better able to recover from both liveness and safety failures -- precisely because it both (1) provides a computational method for ranking fork quality, and (2) allows anyone to participate in producing a fork at any time. If the canonical chain is 51%-attacked, and the attack eventually subsides, then the canonical chain can eventually be re-established in-band by honest miners simply continuing to work on the non-attacker chain. In PoS, block-producers have no such protocol -- such a protocol cannot exist because to the rest of the network, it looks like the honest nodes have been slashed for being dishonest. Any recovery procedure necessarily includes block-producers having to go around and convince people out-of-band that they were totally not dishonest, and were slashed due to a "hack" (and, since there's lots of money on the line, who knows if they're being honest about this?).”

[1]: https://news.ycombinator.com/item?id=26810619

[iownzerobtc]

I haven’t looked through the entire thread but the challenge of recovering from a PoW 51% attack is that the attacker still holds ASIC mining power and can re-attack each new fork. The same is not true in PoS where the attacker’s funds can be targeted and effectively depleted in a fork, leaving it prohibitively expensive for the attacker to continually attack each new fork.

See the “spawn camping” description and defence in my prior link.