The amount of time that people spend in mobile apps has jumped by 21% over last year, which means the average session length is longer than ever. Furthermore, the average number of sessions for an app is also higher than ever. According to data from Localytics, the average number of mobile app sessions per user (i.e., the number of times users open an app) has jumped by 22% from 9.4 times a month in 2013 to 11.5 times per month in 2014.The data shows that specific types of mobile apps are experiencing much higher increases in "time in app" than other types. Coming in on top are music apps, which have seen a 79% increase (64 minutes per month) in time in app between 2013 and 2014, followed by health and fitness (51% increase or 22 minute increase), social networking (49% increase), travel (28% increase), entertainment (22% increase), sports (16% increase), games (14% increase), and news (12% increase).Today, time spent using mobile apps is greater than the amount of time people spend on desktop websites. For content publishers that focus on music, health and fitness, travel, and entertainment, the strategic focus needs to shift from desktop to mobile in order to mirror changing audience consumption habits.Not only has the amount of time people spend in mobile apps increased, but also, individual session length data and number of app launches provide us with insights as to how people are engaging with content via mobile apps. For example, the average session length for a music app is 8.9 minutes (the longest of all types of apps tracked), and the number of music app launches per month is 16.3. The story for social networking apps is very different with the session length just 2.5 minutes, but the number of app launches per month is significantly higher at 25.1. On the other hand, news apps have an average session time of 6.0 minutes and are launched an average of 15.4 times per month. In other words, how people use different types of apps has a direct impact on how content is consumed through those apps.If you optimize your content for mobile audiences (and you should) through a mobile app, consider these statistics and tailor your app experience and the content that you publish to the needs and wants of the mobile audience. Overall, app downloads are down in 2014, but apps that deliver content which users want have an excellent chance of being successful if they're customized for the mobile audience and personalized for the individual user. One thing is certain---a one-size-fits-all strategy does not work in the digital or mobile worlds.Image: Ian Barbour licensed CC BY-SA 2.0