Google recently announced the company has shipped 5 million units of its Cardboard virtual reality HMD, but that figure can be very misleading. That definitely doesn't mean 5 million people are using Cardboard on a regular basis. Because from Google's own data, it seems more like 300,000-500,000 people use Cardboard with any high degree of engagement. Look at this infographic from the announcement:

According to Google Play, the basic app itself has been downloaded 5-10 million times. Looking at third party Cardboard apps, only a handful have been downloaded between 100,000 to 500,000 times -- most of the rest, much less. Unless I'm missing it, only this Star Wars Cardboard app has gotten downloads in the 500,000-1 million range. These numbers indicate a strong "one try then bye bye" effect -- the vast majority of Cardboard owners downloading the main app and one or two more, noodling around a bit, then sticking it back on the shelf to gather dust.

Don't believe me? Here's how many VR-enabled videos for Cardboard have been viewed: