Re: Raisch's Attention link

Jean Francois Groff (
Tue, 30 Jun 92 11:57:55 +0200

> As for charging, fairness requires that the link not be activated
> until I have seen a warning (otherwise I might get charged a zillion
> dollars to read the document - just like 900 phone numbers in the
> USA). So this will add complexity to the client.

This is of course very important! But just adding an alert in the
client before spending money is not a complex change. It might just be
annoying to the user (had you rather be annoyed or spend $$$ ?) The
user could also want to authorize access without warning to trusted
data sources, e.g. a pay-by-time database that he uses frequently
(with the stress of the ticking $ clock in the corner...)

> Also, attention links are not sufficient for a charging. They
> support a model where I am charged once per read, no matter how much
> of the document I read. But it seems likely that there might be need
> for other charging models.

For a discussion of the many problems of a read-based charging scheme
(which was to be implemented in Xanadu as an answer to the Copyright
issues), you may want to read a paper presented at the Hypertext'91
conference in San Antonio, by Pamela Samuelson and Robert Glushko,
"Intellectual Property Rights for Digital Library and Hypertext
Publishing Systems: an Analysis of Xanadu" (unfortunately not
available online to my knowledge...)

  Jean-Francois Groff (
  World-Wide Web initiative
  CERN, ECP division, CH-1211 Geneva 23, Switzerland
  Phone +41 22 767 3755 -- Fax +41 22 767 7155
"Life may at times be boring, but is it more fun to be dead ?"
                                                  -- Alcor