A little more than a year ago, I proposed a subscription system for university presses in
Can eBooks Save University Presses? I think university presses would be an ideal place to experiment with a subscription model. Readers who buy UP titles are generally willing to pay more for a book because of its specialty interest. If a subscription model works with these buyers, then it might work with the general fiction reader; however, if it doesn't work with UP readers, I would think it unlikely to work with general fiction readers who are more price sensistive.