Hardening lists against spam attacks

[Toto]

Peter Hendrickson wrote:

> If our custom was to send money to people who make good posts, then
> you could imagine the fee being quite high, say $20, since most of
> the money will be made back.  Voila! We have a wonderful feedback
> system for how much contribution we have made.

   And there would be no possibility of ending up with a forum
consisting
of those with the most money spending all of their time agreeing with
one another.