Relax OP_RETURN standardness restrictions

The discussion between Sjors Provoost and Pieter Wuille on the topic of spam filtration in blockchain networks, particularly within the context of Bitcoin, sheds light on various methods and their effectiveness. The conversation begins with Provoost highlighting that scripts, not specific keys, should be utilized for spam filtration, echoing practices from the network's early days. This approach is deemed necessary only if simpler filtering steps prove inadequate, which is considered unlikely except during instances of flood relay. Moreover, Provoost suggests that these scripts need not be included in blocks and even proposes that a softfork could allow for their pruning after being buried to a certain depth, emphasizing the goal of making spam both unwelcome and costly without necessitating a perfect solution.

Pieter Wuille raises concerns about the viability and financial implications of such measures, suggesting that they might not be as effective or financially neutral as claimed. In response, Provoost counters by asserting the success and efficiency of existing spam filters, even with limited adoption. He attributes the main obstacle to broader implementation to mining centralization and pools limiting miners' options rather than any significant financial burden. Provoost further notes that miners utilizing enhanced spam filters have experienced higher earnings compared to those using standard Core filters, dismissing worries over financial impact as fear, uncertainty, and doubt (FUD).

Additionally, the conversation touches upon policy adaptability and enforcement dynamics between miners and nodes. Provoost criticizes the notion of nodes having to adjust to potentially malicious miner policies, framing it as a misleading argument. He underscores the efficacy of current policy mechanisms in handling spam, which can be quickly adapted to changing conditions, thus rejecting the premise that new, more rigid solutions are required. This exchange illustrates the nuanced debate on spam management strategies within the Bitcoin development community, highlighting the balance between technical solutions and economic incentives in maintaining network integrity.