marginal cost of ecash transaction

[Wei Dai]

On Wed, 15 May 1996 bryce at digicash.com wrote:

> Excuse me?  Here James, have a penny.
> 
> - -----BEGIN ECASH PAYMENT-----
> [... penny deleted ...]

That brings up an interesting question.  What is the marginal cost to
MarkTwain of such a one-cent ecash transaction?  If everyone started
sending each other these pennies, will MarkTwain go broke? 

Wei Dai