This is a cross-post of my answer to a question on Quora:
The growth of indirect competitors in the mobile app space should be taken seriously by mobile game developers.
As late as Q1 2011, the average smartphone user spent 25 minutes a day consuming games on their phones—far and above the largest category of time spent per user on mobile phones. A year later, in Q1 2012, time spent in social networking apps had increased 60% year over year from 15 minutes per day to 24 minutes per day (time spent on gaming decreased 4% to 24 minutes per day). For the first time, another app category is rivaling games. This trajectory of time spent per user per category is expected to continue; it’s possible that time spent on games on mobile devices will begin to trend down as the smart phone app market matures and fragments– and users are forced to make trade-offs between the ever-growing list of apps vying for their limited time and attention.