Liudvikas Bukys

I just came across the following in a David Friedman essay,
Mail Me the Money!, published August 2002:

My email contains much of interest. It also contains READY FOR A SMOOTH WAY OUT OF DEBT?, A Personal Invitation from make_real_money@BIGFOOT.COM, You’ve Been Selected….. from friend@localhost.net, and a variety of similar messages, of which my favorite offers “the answer to all your questions.” The internet has brought many things of value, but for most of us unsolicited commercial email, better known as spam, is not one of them.
…
There is a simple solution to this problem — so simple that I am surprised nobody has yet implemented it. The solution is to put a price on your mailbox. Give your email program a list of the people you wish to receive mail from. Any mail from someone not on the list is returned, with a note explaining that you charge five cents to read mail from strangers. Five cents is a trivial cost to anyone with something to say that you are likely to want to read — but five cents times ten million recipients is quite a substantial cost to someone sending out bulk email on the chance that one recipient in ten thousand may respond.

It’s a pretty good idea.
I must point out back in November 1992, when the “com-priv” mailing
list was where the action was, I made essentially the same proposal,
to quote:

A better “free market” social convention is that senders negotiate
delivery prices with recipients. People who want junk mail from some
source arrange for free delivery, people who don’t want junk mail
demand that senders pay them big bucks for the privilege of putting
something in their mailbox, tricksters try to make money by looking
like attractive targets for junk mail, the mailing list industry is
reborn as high-quality mailing lists become much more important for
reaching your target audience and avoiding the tricksters, an
electronic stamp industry is created for the purpose of organizing
third-party mailing lists that recipients like being on, and a
wonderful equilibrium settles over the network as the financial
incentives are there for people to receive only what they are
interested in.
Unfortunately, this requires a lot of work on the protocol side
(electronic money transfers, stamp authentication), but if the
protocols were there, I think that the social aspects are attractive
enough that people would go through the cataclysm willingly.

At the time, there were a few friendly remarks,from Steve Crocker
and Ken Laws, with Christopher Locke expressing a little interest,
but the itch wasn’t strong enough, nobody implemented or adopted,
so here we are ten years later with a spam crisis — one so severe
that (I predict) this will be the year in which solutions will be
adopted almost universally — and that solution will in most cases
be automatic text classification and machine learning tools applied
as spam filters.

But there may be room still for innovation in money flows
as well, for two reasons: (1) The population of people whose base expectation is “don’t send me email” may become significant —
and that population may have no resistance to adopting new protocols
for “pay me to read this”. (2) This population will balloon because
of the same issues arising on metered portable devices such as cell
phones.

Yes, “bonded senders” are a small incremental step along this path.