( WIRED ) -- What did you do this summer ? Flat World Knowledge stayed busy on campus and now has 40 times as many students and more than 10 times the colleges using their freemium , open-source digital textbooks as they did spring semester . And they did it the old-fashioned way -- one professor at a time . A company is offering digital alternatives to traditional college textbooks . After a sort of beta earlier this year , Flat World was set to announce Thursday that more than 40,000 college students at 400 colleges will use their digital , DRM-free textbooks fall semester , up from 1,000 in 30 colleges in the spring . Digital textbooks remain a nascent business and a tough market to enter . At an average cost of $ 100 , textbooks command the highest cover prices in publishing , outside of only some art and coffee-table books . Demand is artificially inelastic as students are indentured to cost servitude at the whim of college professors who blithely assign titles a student must own if she hopes to do well in a given course . Now , multiply that by four , five or even six courses a semester and you are talking big bucks . By comparison , Flat World has a pricing scheme that starts at zero for online access using a browser , and $ 20 for a PDF , which they believe will be the most popular format . Printed versions of their textbooks cost up to $ 60 . Perhaps best of all : Textbooks are available a la carte , chapter by chapter . But the key buy-in has been from teachers who make the assignments and who , in my college days , could not care less how much the textbooks cost . What 's changed ? `` There has been a mind shift , '' co-founder Eric Frank told Wired.com . A tipping point came a couple of years ago when faculty began to consider the financial burden on students because many of them ( Frank estimates a third ) did n't bother to get the textbook at all . Perhaps more to the point , open-source textbooks -- which are Creative Commons-licensed to allow unencumbered non-commercial use -- make it possible to graft supporting material to the curriculum , rather than the other way around . `` Faculty are notorious for wanting to do things their way , '' said Frank . `` But they always had to cut the foot to fit the shoe . Now , with open source , they can cut the shoe to fit the foot . '' There is virtually no friction involved . A professor can register on Flat World 's site and let students know that the book is available there . No cooperation from a school district or college administration is required . `` Every single class is a fiefdom , and they are kings and queens of their domain , '' Frank jokes . Like any freemium retailer , Flat World depends on enough people buying something , because clearly the business can not be sustained if everyone just opts for free web access . `` What we 're counting on is that people will be willing to pay for different packaging . '' And it will come down to the price points , Frank acknowledges , even when the company develops formats for the Sony e-book reader and Amazon Kindle , as they hope to this year . It makes as much sense to equip students with a device that makes all their reference materials available on demand as to offer a casual reader a complete portable library -- perhaps more . This is a classic chicken-and-egg scenario in which a device-dependent culture needs to evolve alongside new content formats . For this and a variety of other reasons , including the cost of e-readers and for the media they serve up , Frank thinks the PDF will remain the format of choice for students for some time to come ( and the ubiquitous and DRM-free Portable Document Format is readable on the Sony and Amazon devices , anyway ) . `` They 'll move forward , '' Frank says of device-specific e-reader formats . `` But there is so much irrational pricing right now that they 'll move forward much more slowly than they probably should . '' For now , expect a PDF revolution . And what better back-to-school present can you think of for 40,000 hard-up college students in the midst of a recession ? Subscribe to WIRED magazine for less than $ 1 an issue and get a FREE GIFT ! Click here ! Copyright 2009 Wired.com .
Flat World Knowledge offers free access to digital textbooks online . The company charges $ 20 for downloadable PDF-format books . Interest in the company is rising ; the service will be at 400 colleges this year . Still , the digital textbook business remains in its infancy , author says .