Spam promoter on the Bitcoin blockchain (Jameson Lopp) explains how the email protocol lost decentralization due to spam. https://youtube.com/clip/UgkxGzhowIo00Vz8-UZ-RjUxR3F0s3zkqmSY?si=Cannp7BPixjExtdR

Libre Relay (2%) and Bitcoin Knots (21%) represent two opposing camps in the Bitcoin network. Libre Relay removes the OP_RETURN limit and lowers the minimum fee rate from 1 to 0.1 sat/vB. This facilitates the entry of spam into the more expensive Transaction Data (1MB) part of the block, not just the Witness Data (3MB) part, where things like Inscriptions and Ordinals are currently stored. The Witness part is 4x cheaper but more complex to implement and use compared to the Transaction part, as the data is not continuous and requires scripts for reading and indexing. However, if the transaction cost is reduced by 10x, as Libre Relay already does, it becomes even cheaper than the Witness part, which is currently 4x cheaper. Bitcoin Knots retains the 80-byte OP_RETURN limit and introduces anti-spam filters to preserve the efficiency and monetary purpose of the Bitcoin network. Bitcoin Core (77%), as the dominant implementation, has clearly become compromised since v30, as it gradually introduces what Libre Relay is already doing to facilitate spam. It wasn’t enough that spam was already getting through by sending transactions directly to miners like MARA via the Slipstream API and by introducing Libre Relay nodes that remove spam barriers. They also had to involve the Core implementation to make such pro-spam nodes dominant, thereby enabling easier and cheaper entry into the block. Instead of introducing changes to Bitcoin without a clear goal or reason, risking unintended consequences, it would be appropriate to first know the specific reason for increasing OP_RETURN, such as a specific project like Citrea, so we can weigh the benefit/risk ratio.I believe that embedding spam and images is not sustainable in the long term, as they won’t be able to compete with monetary transactions due to the cost of block entry. However, this is a specific moment when the Bitcoin chain is less utilized—partly due to the introduction of ETFs and partly because L2 solutions, though mostly custodial, are working reliably. Spammers can exploit this moment to permanently pollute the chain, thereby threatening the decentralization of the Bitcoin network.