No-one's explicitly mentioned "spam resistance" as a goal yet, despite
the fact that it's probably the biggest reason why we might seek to
replace our existing mail system altogether rather than fixing it. Of
course it's the main motivating factor behind some of the other goals
mentioned, which is why it's worth mentioning it explicitly because
those sub-goals may or may not be the best way to achieve the main
goal.
Borenstein mentioned "attention bonds". A Google search reveals they
refer to this research:
http://www.citi.umich.edu/u/rwash/projects/spam/
the proposal being that I lodge a dollar (or a cent) with a third
party in your name before mailing you, you read the mail after
checking that the dollar is there, and if I decide the mail is not
spam the dollar is returned to you. Unfortunately it appears the idea
is patented.
PETmail's primary motivation is spam resistance. It requires that
every mail be accompanied by evidence that you might want to read it.
This might be simply a cryptographic signature from a known
correspondant, or something more sophisticated: a third-party
introduction, or proof that they have passed a CAPTCHA test, for
example. I only learned about it a couple of weeks ago and I think
it's very impressive - I don't think it should be adopted as an
Internet mail successor, but I hope that successor has its strengths.
It also uses Mark Miller's "pet names" idea to think about namespaces.
PETmail: http://www.lothar.com/tech/spam/
CAPTCHA: http://www.captcha.net/
Pet Names: http://www.erights.org/elib/capability/pnml.html
I look forward to hearing about other proposals for inherently spam
resistant email.
--
__ Paul Crowley
\/ o\ sig(_at_)paul(_dot_)ciphergoth(_dot_)org
/\__/ http://www.ciphergoth.org/