David Evans, of the University of Chicago Law School and UCL, has made available an innovative book, Essays on the Economics of Two-Sided Markets: Economics, Antitrust and
Strategy. The subject matter is apparent from the title, and there look to be some interesting and useful papers here.

The format is interesting too. It's a downloadable pdf which contains links to freely-available versions of each paper. There is an author's preface commenting on the economics of publishing which is worth quoting in full:

“Given the subject of this collection, there is some irony in how I’ve chosen
to bring these essays to you. Publishing has traditionally been a two-sided model.
Publishers get authors and readers together. They typically make their money
by charging the reader and giving some fraction of the earnings to the author as
royalties.

This 20th century model of publishing doesn’t serve authors of academic
books well. Often, publishers set the price of academic books relatively high,
expecting to earn the greatest profits from libraries and a handful of aficionados.
For most books that aren’t aimed towards a popular audience, including most
academic books, royalties are quite small. Optimistically, I might have been able
to buy a pretty good new bicycle if I had published these essays in the traditional
fashion, but I’d rather have more people read my work than collect the chump
change from royalties.

Therefore, the two-sided publishing model fails in two ways: the author
doesn’t make much money, and the author doesn’t get read by very many
people. Moreover, most publishers in my experience are still using 20th century
technology to produce and distribute books. It can take many months—if not
years—from a book’s conception to its appearance in a reader’s hands.
The irony is apparent that, in order to bring my work into the 21st century,
I have decided to publish my collection of essays about two-sided markets in a
one-sided way. I ditched the intermediary and chose to connect directly with
likely readers. I’m sure some of you would prefer the feel of paper and leather but
hopefully the price is right. It was easy for me to decide to make this volume free
because it cost almost nothing to produce and distribute it.

This version of the book consists of a series of urls (website addresses) that
will take you to the original papers. It is easy to download and store them as pdfs
on your iPad or whatever e-reader you use, as well as on your personal computer.
For those who find multiple downloading inconvenient, just wait: I am planning
to release a downloadable pdf of the entire volume in the early part of 2011. It
will have all of the chapters available in a single download.

This approach is novel, and no doubt imperfect, but I’d like to make it better
next time. Please feel free to post your comments on the LinkedIn group that I’ve
created (Two-Sided Market Economics, Strategy, and Law) or email me directly
at david.evans@competitionpolicyinternational.com with your suggestions.”

I'll contact Prof Evans myself in a while to see how his publishing experiment is going.