Micropayments have long been the holy grail of internet publishing.

"Users should be willing to pay, say, one cent per web page in return for getting quality content and an optimal user experience with less-intrusive ads," web-usability guru, Jakob Nielsen wrote back in 1998.

"I predict that most sites that are not financed through traditional product sales will move to micropayments in less than two years." But nobody has yet managed to crack the nut.

No micropayment company has ever managed to get more than a handful of sites to sign up. Publishers have a hard enough job persuading readers to pay for content; they're inevitably doomed to fail if people have to sign up for a different system on every site.

The best hope, ironically, lies with a company as pervasive as Google, which has the clout to persuade people to join such a scheme.

But Google's Checkout service isn't yet tailored for micropayments, while PayPal's so-called micropayment system also levies $0.05 on every purchase, as well as taking a 5% cut. The hunt continues.