1.) Chaum's e-cash coupled with WWW/Mosaic is a de facto internet mercantile protocol.
It ain't de facto until a lot of people are using it. I suspect PGP with credit card numbers in free-form ASCII is almost as common, at least for now; there are 4 or 5 groups I've seen that will accept that. And phone calls or faxes to the number on the bottom of the ad on Usenet probably outmumber those... In particular, digicash isn't a standard until there's at least one bank a lot of people can access via digicash. However, it's certainly a nice approach. Credit cards do take care of one of the objections Hal mentions, which is how you can trust your vendor to ship you the goods instead of absconding with your cash. Some of the digicash protocols can help with that process, at the cost of privacy - the spender can reveal the number of the coin that was ripped off, but the receiver may have cashed it via anonymous remailers, making it difficult to prove who's telling the truth in court, especially when the goods were software delivered by anonymous remailer chains as well. Bill