New business model - "Fair use" - JAJAH - web-activated telephony

Interesting service announced today from the new startup Jajah (Yair Goldfinger, ex. ICQ is one of the investors). They provide a free service but ask to limit the usage and use some of the paid services. Can't say this is a truly business model, sounds more like an eye-balls like model...
JAJAH - web-activated telephony: "What’s the JAJAH “Fair Use” Policy ?
The Jajah “Fair Use “ policy asks our users to “play fair” and behave in a manner that best serves our greater calling community. We ask that you limit your free hours to about an hour a day, five hours a week,or about 1.000 minutes per month. If you use it more than that, we ask that you also use some paid JAJAH services such as text messaging (or scheduled calling?) We can only offer the free service if enough people also use some paid services. "