Virtual currency has fast become a multi-billion dollar industry. It’s
the juice that could propel Facebook to great IPO heights, and has already served as the foundation for other billion-dollar businesses,
like social gaming giant Zynga.

In fact, a study released yesterday from Juniper Research predicts that the amount of money being spent on virtual currency in mobile apps is going to more than double in the next four years, going from $2.1bn last year to $4.8bn by 2016.

If Juniper’s prediction comes to pass, it will obviously be good news for mobile developers. Mobile apps are a billion dollar business, but monetisation isn’t always easy. Significant competition has, in some app categories, made it all but impossible for most developers to charge more than a dollar or two for an app.

Enter the great equaliser, virtual currency, which gives app developers the opportunity to offer up their apps for free and monetise once users start using them. As GigaOm notes, a recent report found that over half of the top grossing apps in both Apple’s App Store and Google’s Android Market are freemium apps, and these are the apps that most frequently take advantage of virtual currency.

With smart phone adoption continuing to grow at a rapid pace, it won’t be surprising to see more developers turn to virtual currency to support freemium business models.

Virtual currency, of course, won’t be a panacea. At the end of the day, it’s still just a potential source of revenue. Mobile app developers will still have to build compelling apps if they want to compete, and increasingly they’ll need to build even more compelling virtual currency-based experiences if they want to cash in. In other words, the mobile virtual currency pie may very well more than double in the coming years, but that doesn’t necessarily mean that a larger number of developers will be eating more pie.