A new app that originated in Germany and is soon coming to America has an interesting pricing model that encourages word-of-mouth subscription registrations.Blloon is an eBook app with a “catalogue of almost one million titles” that offers users a freemium subscription model. The “Free” level requires no up front subscription fees, just registration with an email address.However, the site does have some novel rules around usage; users immediately start with access to 1,000 pages, which is about the equivalent of two books. By limiting pages, not titles, users can jump between titles at will.When the free pages run out, Blloon lets users earn more through a sort of gamification scheme where providing feedback on the app gets you 100 pages, referring a friend to sign up is worth 200 pages and following them on Twitter gets you 50 pages (although that last one is a one-time-only proposition). Future releases are slated to offer the ability to review books for extra pages as well.These additional page rewards were developed in part because Blloon hopes to engage the 18-30 year old market, a traditionally slow cohort to adopt paying for eBooks. Writing a review or signing up a friend has benefits to both the app and the customer.For those who want to skip the games, the “Easy” level subscription is $6.25 a month, where subscribers get 500 pages every month.Finally, a “Premium” level allows users access to 1,000 pages a month for just under $11.00. Additional purchases of 100 pages can be made for about $2.00.While it seems that Blloon probably won’t be for the most voracious readers among us, more casual readers who don’t want to necessarily shell out cash to read some of their favorite titles may find this attractive.At the same time, the page-count focus can be confusing for prospects – there’s no clear line between free and paid content, just amount used. All of the research we’ve gleaned over subscription content best practices makes us skeptical of the long-term success of such a model. What do you think?