Data released from SuperDataResearch shows that Blizzard's collectible card game Hearthstone has been on an absolute tear since launching on mobile. In fact, the mobile version of Hearthstone just surpassed the desktop client in terms of monthly revenue. The only reason it looks like it took so long is that for most of the game's early release, it was only available on tablets and 6+ inch smartphones. That all changed when it launched on iOS and Android for all smart phones on April 14, 2015.

Hearthstone has been tremendously successful on the PC and brought in over $114M in revenue in 2014. With the game's successful mobile launch, it'll likely increase revenue significantly in 2015. Hearthstone's mobile success can be attributed to the game's excellent port to mobile devices. The mobile version doesn't segregate players either, meaning mobile users can use their existing Battle.net accounts and face off against opponents on the PC. Given Hearthstone's enormous success on both mobile and desktop, expect upcoming collectible card games like Hex and Infinity Wars to hasten their mobile development.

Edit: Here's an awesome edit someone posted on Reddit, adding some additional details to the original chart. (Thanks /u/arktal). Also many users have correctly pointed out that buying packs on mobile is often cheaper and more efficient for European users than on desktop due to additional payment options being available. This reduces desktop purchases and boosts mobile ones. Still, the inevitable growth of mobile continues. I'll update this chart when new data is available.

Source: Superdataresearch