Social networking apps are challenging games as the most popular titles for smartphone users, according to analytics company Flurry.

The company said that when measured in terms of minutes of use, games and social networking apps are now tied, at 24 minutes per day. Significantly, when compared to the first quarter of 2011, use of games has decreased from 25 minutes, while social apps grew from 15 minutes.

Indeed, social networking apps are largely driving the increase in app use – categories, such as news, entertainment, and “other,” were largely flat in terms of use.

Flurry also tracked the distribution of revenue between app developers using its AppCircle ad network. Here again, social networking is the category on the move, growing its share from 24 percent in February 2012 to 37 percent in April 2012.

Interestingly, this was not at the expense of the games category, which saw its share increase from 35 percent to 36 percent.

It was the “other” category that was squeezed (Flurry split spend into three), shrinking from 41 percent of the total to 28 percent.

The company noted that “this is the first time in Flurry’s history that any category has surpassed games in ad revenue generation,” since it launched its services in summer 2010.

It warned: “as we reach saturation for mobile gaming on a per-user basis (one consumer can play only so many free-to-play games), the games category could start behaving more like a ‘zero sum game’ from here on out, meaning that games companies would have to fight over a finite group of consumers in order to grow their businesses.”

“For one app to grow, it would have to take from its competitors,” Flurry said.