Big fan. Been using it for a few weeks. Really enjoy the competitive aspects (challenges, badges etc.) - good for the motivation. Not sure if this is a reasona

Big fan. Been using it for a few weeks. Really enjoy the competitive aspects (challenges, badges etc.) - good for the motivation. Not sure if this is a reasonable business model but I'd certainly pay for an iPhone app.. Perhaps premium features? Admittedly I can't think of anything off the top of my head..