According to the below chart prepared by Data Analysis Company ‘Statistsa’ and Data Published by ‘GlobalWebIndex’, ‘Google Map’ is most used smart phone app.
This data is collected in past month (Q2 2013) and based on total % user worldwide.
1- 3 apps are developed by Google out of top 4 most used apps.
2- 3 apps belong to social networking sites (Facebook, Google+ and Twitter).
3- 4 apps belong to chat/messaging category (WhatsApp, WeChat, Facebook Messenger and Skype).