While Facebook recently made a technologically-sound decision to push virtual reality, it may have trouble growing its revenue from its social games under the social network platform.

According to a company announcement on its investor page (via Gamasutra), its users are currently moving from using the site on their desktop computers to accessing them on smartphones and tablets.

According to CFO David Ebersman, the mobile shift is significant as Facebook’s game payment revenue comes from the desktop site and that will slow down as more people start accessing Facebook to play games on their mobile devices. “Growing this [games payment] business going forward will be challenging.”

Compared to last time when Facebook’s games revenue was at eight per cent during and before 2013, it went down to just one per cent year-over-year during the first quarter of 2014. On a whole, the company’s payment and fees revenue was US$237 million for that same first quarter, which was 10 per cent more than the US$213 million the company got from the first quarter of last year.

While the social network company is planning on transitioning to mobile for the sake of adapting, its focus is still on improving is advertising business on its desktop version. To be fair, the company makes a lot more from the latter method.

Facebook posted its revenue stats for the first quarter of 2014, in which it earned US$2.5 billion in revenue.