• by Mark Walsh  @markfwal, February 21, 2012

Raj Aggarwal, CEO of mobile app analytics firm Localytics, wraps up OMMA Metrics with insights into mobile app trends and metrics. Android and iOS have obviously outstripped other app platforms in growth, with the latter still the dominant player. Android tablets are converging around 7-inch screen size regardless of manufacturer, a positive development for developers.

Aggarwal says Android fragmentation is overstated—if developers focus on most pervasive Android devices, their apps will reach the vast majority of users. When it comes to HTML5, he says pure HTML5 apps are still far off, though hybrid apps are growing. You need to use app-like tools to build apps with the Web-based format.

Regardless of platform, holding onto app users is hard—about 30% use an app once and move on. That’s why it’s so important to get it right in development, to keep people from ditching an app after one or two sessions. App engagement varies by category--news titles to have the longest sessions while games have shorter bursts of use between different activities.

Looking at app measurement, Aggarwal points out that apps can’t be reduced to a series of page views, like a Web site. They have unique IDs instead of cookies—that has challenges because they change over time and can be more difficult to track. So Web methods can’t be applied to app measurement.