Earlier quoted context omitted.
Postal mail and telephone were ... relatively secure, inasmuch as that bulk surveillance was expensive . Wiredtapping and postal interception, as well as metadata (pen-trace and postal covers) are possible, but scale poorly when individual lines must be listened to by individual agents, or individual letters carefully opened and resealed. Digital permits surveillance at mass scale. It seems ultimately a fundamental p…
I would argue that postal remailing exposes the remailer to legal risk, and (if done with few remailers) gives the surveillers few points of particularly interesting mail hubs. If anything, postal remailing would probably only work in a TOR-like manner, with many, distributed, non-for-profit remailers - but that opens a whole set of new problems, like who pays for the service, what prevents the remailer to just take…
Even as an informal practice, the option could have some value. The question of whether to used a two-hop (source, mix, recepient) or three-hop (source, mix-1, mix-2, recipient, as with Tor) exists (the three hop system would triple postage, if messages were sent individually, though bulk distribution is another option, with break-bulk at the 1st or 2nd hop).
Again, what has surprised me previously is that I'd found no mention of the concept at all. Though I am finding several now, specifically emphasizing anonymity / location obscuring: