Latest statistics from Flurry explain how, with iOS and Android devices being adopted faster than PCs, more people are choosing to spend their time in front of mobile devices.
Furthermore, people are increasingly choosing mobile apps rather than browsing the web. This is especially so for social networking that makes up a large proportion of people moving from web to app.
What does this mean for mobile developers apart from the need to possibly social-enable your app? I recommend you take a look at Randy Ksar’s presentation on the Motodev blog. It explains some ways you can use social sharing to promote and improve your app.