This article is from the Douglas Adams FAQ, by Nathan Hughes nhughes@umich.edu with numerous contributions by others.
From a blurb posted in alt.fan.douglas-adams:
The complete content of the first four books can be purchased for a total
of five dollars. How? Over the web, in electronic form!
The Hitchhiker's Trilogy has been a staple of Voyager's Expanded Books
line, and can now be purchased and downloaded from our web site
(http://www.voyagerco.com/). Using a new web technology called TRADES, you
can now purchase digital content safely and efficiently over the web. No
password. No account number. No "cybercash." No mailman. No paperwork.
Just enter your credit card number, and follow the simple directions for
downloading your own copy of these books! And since we don't have to pay
for floppies, packaging, and distribution, we can afford to offer these
titles for only 5 dollars! To find out more about TRADES, purchasing over
the web, and Hitchhiker's, go to:
http://www.voyagerco.com/TRADES/trades.html
Expanded Books are books designed to be read on your computer. Douglas
Adams is a big fan of them. Really! You don't believe us? We've got
proof--just point your browser to:
http://www.voyagerco.com/TRADES/what.html
and hear Douglas discuss the wonders of the Expanded Book.
Peter Merholz
V O Y A G E R
http://www.voyagerco.com/
 
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