>If the technology is deployed by 100% of the community providing >professional email operations, both on the sending and the receiving >sides, as Dave expects, ... I'm not Dave, but I cannot imagine where you got the idea that he expects the "community providing professional email operation" to deploy 100% of anything. The idea that big mail systems will form a cartel and lock out people who won't pay is just silly to anyone who remembers the history of e-mail. There used to be lots of closed commercial email systems, including AOL, Compuserve, and MCI Mail where Dave worked. Without exception, they all were swept away by Internet mail which was cheap, universal, and unmetered, even though in some ways it was technically inferior to those systems. Some of them, like AOL, morphed into ISPs, others like MCI Mail just died. If some group wanted to build a closed pay-to-play mail system, they could do it with the tools they already have, using SMTP AUTH or STARTTLS with a private signing cert or VPNs or whatever. The reason they don't is that it makes no sense, and a tiny tweak like VBR isn't going to change that. Is there any possibility that you are confusing threats that are easy to imagine with threats that are likely? Because this one isn't likely. R's, John _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf