Carlos on Nostr: I agree, its the relays who face the brunt of the spam, so they have to deal with it ...

I agree, its the relays who face the brunt of the spam, so they have to deal with it the most.

IMO there are 2 ways to go about it:

1) Paid relays. This means only members can post. This means free relays are left behind, vulnerable to spam attacks. Which is a disaster for onboarding, as new users will basically have to pay to post on nostr.

2) PoW. Just like Tor is using PoW to defend against spam attacks, relays can dynamically ask for PoW for new events, or even for subscriptions. Higher relay load = higher PoW needed. PoW means constant work for spammers and only occasional work for honest posters. If you look at the bigger picture, it exponentially harder for spammers to attack multiple PoW relays at once. This is good news for honest users, who will likely be using a few relays: if some relays are under attack, the others are likely not, so you can still post at a low or no PoW threshold.

Either sats or mining, it comes down to a provable cost. At the end of the day, sats are PoW are interchangeable. You can buy PoW with sats, or sell PoW for sats.

TL;DR: With PoW all relays, including the free ones, have a chance to ward off spam atacks.