“Freemium” has been much more than just one of the biggest buzzwords of 2011. Worldwide, of the top-ranked 250 iOS apps across all categories, an average of 88% are already free to download and monetized incrementally with advertising and in-app purchases. The trend will continue in 2012, and it is entirely possible that at this time next year in certain categories all relevant iOS apps will be free.

Apple enabled in-app purchasing for free apps in October 2009, and since then developers have been remarkably quick to evolve their business models. Aapo Markkanen, senior analyst, consumer mobility, explains, “What many observers misunderstand about freemium is that it isn’t only about monetizing, but…