Distimo has published its app analysis for 2011 and, hidden amongst some other semi-interesting findings, are details of the real success story of 2011 in the app world (that being a world that is app mad, rather than a portfolio associated with BlackBerry) - free apps that make money.

The freemium model appears to be booming with Distimo's mobile application store analytics suggesting that in-app purchases from free apps accounted for half of the revenue of the 200 top grossing apps in the Apple App Store and an even higher 65 per cent in the Google Android Market.

This indicates a shift in the developer approach whereby the apps themselves cost nothing originally for the user, but will end up costing over time. A perfect example is EA's Tiger Woods golf game on the iPad, which has been offered for nothing on a few occasions throughout the year. Once you get playing, you soon realise you're going to need to fork out for some in-game money if you are to play the big PGA tournaments and improve your game.

Distimo also states that Apple is still dominating Google at the top end, with both the Apple App Store for iPad and the Apple App Store for iPhone out scoring the Android Market in terms of the total revenue generated by the 200 highest grossing apps. 

Other notable findings include a Windows Phone 7 Marketplace growth, in terms of apps on offer, of more than 400 per cent year-on-year, and the Amazon Appstore becoming larger than both the Nokia Ovi Store and BlackBerry App World in terms of available games.

You can download a PDF of the analysis for yourself over on Distimo.com.