Pay per use remailers and remailer reliability tracking.

[Dr. Evil]

> A token-based remailer system, while an "obvious" system, would be a 
> major accomplishment.

Any kind of privacy-enhanced token/payment/value system would be a
major accomplishment at this point.  The c'punks have been in biz for
almost ten years now, and private payments have always been probably
the #1 goal, and we are _further_ from having a private payment system
now than we were ten years ago.  We've got the math.  We don't have
the software or the business, though.

The reasons for this have been debated over and over.  We're at an
impasse.