Apple's App Store and the Google Play store each claim to offer over 700,000 apps to choose from, but only a tiny fraction of them bring in significant revenue for their developers, according to research from analyst firm Canalys.

In fact, the company says, of the $120m in total revenue generated from paid app downloads and in-app purchases in the US during the first 20 days of November 2012, fully half was split between just 25 developers.

Top 25 Developers Taking Half of App Store Revenue: Majority Being Games [theregister.co.uk]