Oh, one other thing I wanted to comment on: you mention that it's more realistic to have makers pay than takers. I think it's hard to know, because both sides have advantages, but ideally, you just let the market figure it out. The problem I always had was, while a negative fee (i.e. makers pay to take part) is clearly possible in software with trivial changes, it's a scary concept to have makers passively ready to do unlimited transactions where they lose money. I guess you could attack it from a number of angles, such as just rate-limiting. Hmm on reflection not sure why this wasn't pursued more. But anyway the off band payments would indeed be the "royal road". I know indeed that several people, including Peter, have suggested that a system like this could work way better with no inter-participant payment at all. I wasn't convinced that a zero-fee version would work, but, for sure, there's an argument for implementing that, too. Best would be a complete free market if that were practically possible.