Micropayments? - Just Ask Millicent

Here's an interesting idea for academic publishing: micropayments as an alternative to standard subscriptions or open access. There's just one problem: micropayments have persistently failed to take off. Just look at what the W3C page on the subject says:

W3C has closed its Ecommerce and Micropayment Activity

and I don't think it was because of overwork.

Or take Digital's Millicent. I wrote about this in April 1997, when it looked highly promising. Afterwards, nothing happened, despite its evident cleverness. Today, the Millicent site is still listed on the W3C micropayments page, but so far has steadfastly refused to answer my insistent calls....