> Sender reputation where you block smaller email providers indiscriminately without weighting DKIM signatures or identity That's not true. > because nobody b

> Sender reputation where you block smaller email providers indiscriminately without weighting DKIM signatures or identity That's not true. > because nobody believes that Google is going to send spam mail. This sentence indicates you don't know much about who sends spam or not. > The computational cost is imposed on non-Google players You're going in circles. Do you not see how that especially is unfair to the smaller players? Spammers have just as much compute, it will just impose an additional burden on the legitimate senders. So in your scenario a small startup has to wait tens of minutes (bunch of letters in the queue already) to send email confirmation letters. The spammer on the other hand does the same, it'll infect a few more devices, they've exeeded the startup's sending rate. Alternatively, both the spammer and the hypothetical startup build reputation first. They'll warm up the domain, both get to send more in the same timeframe. So... we're at the beginning again, everyone warms up their domains and IP's like they do right now. PoW hasn't improved the sitation. > I don't see what your point is here. Because you haven't seen enough spam. On average everyone is incentivised not to accept mail from new or unknown domains. > everyone is incentivized to accept legitimate, non-spam email from all of their customers No shit, but also not the topic. Received mail is not perfect, that's what's the actual topic.