A new anti-spam idea

Tim Bray offers the first first concept
for paid email I’ve seen that might actually work.  The basic idea
of using an economic mechanism to prevent spam has been hashed over
many times.  One big problem with such mechanisms is that they
break the decentralized, open architecture of email.  Tim’s
solution is to have intermediaries that serve as relays and collect the
money.  The endpoints wouldn’t have to change. 

I still don’t see such a mechanism becoming ubiquitous.  There is
still the question of getting such a system to critical mass, and
various implementation problems.   But for active email users
(like yours truly) I could imagine it becoming then norm instead of
challenge-response systems.