Nielsen published data on the most popular iPhone and Android apps of the year. As you can see it’s mostly meat-and-potato type apps like maps and weather. The two apps that amusingly stand out, and sort of tell stories about each platform are “Advance Task Killer” for Android and “Instagram” for iPhone.
The first app you need to download when you get an Android phone is Advance Task Killer, because Android’s apps will be aggressively acting up in the background killing your battery. Advance Task Killer helps control your phone. It’s addressing a flaw within Android.
Instagram, on the other hand, was an iPhone-only app for a long time, becoming hugely popular. It eventually sold to Facebook for $1 billion.