You may have heard of virtual reality (VR). You may have even used it once. And then you might have thought it was just a passing fad.

But there are quite a few people who think otherwise.

On Wednesday, Facebook owned Oculus announced that over a million people used Samsung's Gear VR headset in April. Oculus, which Facebook bought for $2 billion in 2014, provides the software for Samsung's device.

Oculus also said developers have created more than 250 apps for the Gear VR, highlighting the attraction of VR platforms for developers.

While the numbers may seem small, it's only been six months since the launch of the Gear VR and analysts said the numbers signal growing momentum for the technology, albeit with a cautious approach.

"If you stand back and get beyond all the geeks shouting about it, you could say these numbers deliver cautious optimism for the potential of VR and 360 degree content," Ben Wood, chief of research at CCS Insight, told CNBC in a phone interview.

"VR isn't just something that's a thing that goes on you head. But it is also about the fact we are seeing a whole ecosystem built around it and with the marketing Samsung and Facebook are putting behind it, it's getting more prominent in the consumer consciousness."