One key insight of Bitcoin is that transaction fees control spam and that's how we treated it on the consensus layer since day one. Nodes had policy to fight spam if they wanted to but spam in blocks was never the target of preventative measures. Never was a block rejected because it contained spam. Spammers increasingly worked around the Bitcoin broadcast mechanism for transactions driving miners to seek tools to get those mining fees. This put small miners at a financial disadvantage leading to mining consolidation in big pools. Enter bip110: It's proponents want to stop spam through consensus. But fighting spam is a notoriously tedious arms race where in this case, the defender would be at a disadvantage of galactic proportions. Any spam counter-measure would get deployed through a months long fork process with real risk for people building actual money tools using OP_IF or anything a fork would ban willy nilly from tomorrow on while the spammers would get plenty of head notice to change how they store their rock pictures on Bitcoin starting at that and that block height. That said, was the OP_RETURN limit removal sensitive? No! I wish we had kept it at some 200B or something where it would not limit anybody building selfishly data storage tools but also it would not have signaled to retards that Bitcoin was open to 100kB file storage. In the end, bip110 is crazy madness promising to fix spam which it can't and it will do more harm than good if it wins or if it looses: 1. If it gets largely ignored, spammers will say "see, Bitcoin loves us!". 2. If it gets some fork chain to wither for some years, spammers will say "great, now that Bitcoin Knotzy forked off, Bitcoin loves us!". 3. If it gets enough traction for nobody wanting to risk being on the re-orged side of the chain split, Bitcoin will die because we will have anti-spam forks every other week, we will not talk about anything but fighting spam and Bitcoin will turn into a total joke. 4. If Knotzy gets some scary 30% and decides to still build their chain and through whatever freaky incident they get their chain to grow faster than Bitcoin later, Bitcoin would defensively hard fork which would be the absolutely worst of all outcomes but the one, Knotzies allude to in their marketing. So clearly I hope we go with option 1 and not being in the Knotzy bubble I'm pretty convinced that's what's going to happen but maybe I'm in the Core bubble and wrong?

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Ok, to be fair, that’s a better answer than I usually get. Still not compelling, though. It only models worst-case scenarios materializing while ignoring second-order effects from aggressively countering spam, and the uphill battle that creates for spammers who are determined to build a marketplace on Bitcoin. You’re partially correct in assuming fees were one of the tools historically used to combat spam — particularly DDoS-style flooding and steganographic data stuffing. But fees alone are not equipped to fight the new form of gamified spam that emerged in early 2023. That situation could have been prevented if decisive action had been taken early on the Core side, before an entire economic ecosystem formed around this behavior. The simplest mitigation was fixing the witness discount loophole that allowed spammers to bypass existing filtration policies. Instead, it was reframed as a feature rather than a bug, which effectively incentivized spammers to organize crowdfunding campaigns, build specialized tooling, and even open direct submission channels to miners. Once that marketplace for gamified spam took root, fee pressure stopped being an effective deterrent. Spammers weren’t paying fees as a cost — they were treating them as speculative inventory, expecting to recover them by selling their “art” to the next buyer. At that point, the lenient posture from Core — which effectively held a monopoly over standard spam filtration policies — signaled that this new bazaar would not face meaningful resistance. The results are visible three years later. The UTXO set expanded from roughly 4 GB to 12 GB. Spam occupies approximately 36% of blockspace, and around 76 GB of additional blockchain data now exists that likely wouldn’t otherwise. Meanwhile, for the first fourteen years of Bitcoin, mempool policy and fee pressure were sufficient to keep non-financial data at near-zero levels. That wasn’t accidental. Developers and node operators largely shared the same expectations regarding arbitrary data storage, and spammers respected those norms because they knew they would face consistent resistance otherwise (Vitalik’s early experiments are a good historical example). Today is a different environment. The core issue is that protocol maintainers shifted from treating spam as adversarial behavior to treating it as inevitable (Gregory Maxwell’s posts from 2014-2015 illustrate the earlier philosophy clearly). Your argument against BIP110 — particularly scenarios one and two — assumes spammers are still deciding whether Bitcoin welcomes them. That decision has already been made. The derogatory label “Knotzis,” often thrown around to dismiss policy-focused Bitcoiners, originated within those spam-aligned communities. BIP110 is one of the first proposals in years that has visibly unsettled them, as evidenced by recent commentary from the primary Ordinals wallet provider. For the first time in a while, their business assumptions are facing uncertainty. Regarding the claim that spam revenue disadvantages small miners and accelerates pool consolidation — current data does not support this. Spam transactions have contributed less than 0.76% of total miner revenue over the last three years. Mining centralization is far more strongly tied to structural incentives created by the FPPS payout model. If the mining ecosystem genuinely wanted to address centralization, transitioning toward DATUM-style template construction could significantly reduce pool dominance, while simultaneously making spam dynamics even less economically relevant. Now consider OP_RETURN. The justification for expanding its size limit by roughly 1200x was that it would channel spammers toward less harmful data-embedding methods. If that theory were correct, inscription-based spam should have declined. Instead, both vectors are now heavily utilized, transforming a single problem into two parallel ones. There has been no meaningful accountability, no serious exploration of alternative mitigations, and no acknowledgment that the policy experiment failed. You argue that fighting spam at the consensus level becomes an endless cat-and-mouse game. Ironically, the same argument was previously used by Core developers against policy-level filtering: that filters were insufficient and only consensus changes could address spam. The goalposts appear to move depending on which layer is being discussed. Spam mitigation is inherently adversarial, but the asymmetry still favors defenders. The objective is not to eliminate spam perfectly — it is to disrupt the economic viability of spam markets. Once profitability is destabilized, fee pressure and policy friction naturally reinforce the defense, exactly as they did for over a decade prior to 2023. If BIP110 fails to produce a measurable reduction in spam incentives, alternative proposals like CAT directly target spam marketplaces themselves. In combination, they would likely be devastating to the current spam economy. Realistically, activating both simultaneously may not even be necessary. Once complacency disappears and profitability declines, speculative “Bitcoin-native” token experiments will follow their historical pattern and migrate elsewhere.
I think the problem is black/white thinking on both sides. There's a difference between spam and legitimate non-monetary use cases. Ideally, a reasonable balance could be found by earest and pragmatic developers and Bitcoin service providers. Uncapped OP_RETURN with no filters is too extreme and an obvious hazard. I support L2s, timestamps, etc. but they don't need such extremist and dangerous default settings.