The Iconfactory has changed their business model for Twitterrific making it a freemium app rather than a paid app at £1.99.

This means anyone can download the app for free as an ad-supported application. There is also a selection of unlockable features available as in-app purchases.

Features such as the today view, translation and removal of ads are now offered as paid upgrades. Most notably, enabling push notifications now requires a paid upgrade.

I just wonder if this is the future of all apps. What do you think?