Facebook doesn't really have much to prove when it comes to user numbers. It's already got over one billion people using the site at least once a month every month.
You can't go much further from here, there are only a couple of billion people with internet access in the world and a few hundred million of those are in China, where Facebook is blocked.
But that doesn't mean Facebook isn't worried about growth. In fact, it may be more worried than ever as the world goes mobile.
Granted, the Facebook mobile apps and websites are as popular as ever, but Facebook can't rest easy, the mobile space is still quite volatile and the next Instagram could be around the corner.
It can't buy any mobile company that becomes popular, so it has to make sure its own apps are great.
It's not doing so bad, it's got well over half a billion people using the mobile version of Facebook, 604 million at the last official count.
But if you're looking for more specific numbers, you're going to have to look elsewhere. If you know where to look though, you can seek out some info.
Analyst Benedict Evans did just that and he came up with some interesting stats. For example, Android is clearly becoming the dominant force, there are 192.8 million people using the Android app each month as of November last year.
That's compared to just 147.2 million on the iPhone. Granted, the Android number includes tablets, but there are so few of those it's more of a rounding error.
If you take into account the iPad though, iOS looks a lot better, with around 48 million iPad users as of September 2012, there are more iOS users than there are Android users.
But Android usage is growing fast compared to iOS. Not only that, but penetration rates favor the Android where only roughly 35 percent of owners have the Facebook app installed. That's compared to 73.6 percent for the iPhone and only about 48 percent for the iPad.
Also promising is feature phone usage, the Facebook for Every Phone Java app has some 82 million monthly active users.
And if you're wondering why nobody is developing for Windows Phone, to Microsoft's desperation, the Facebook app only has a couple million users. Granted, the Facebook app for Windows Phone is very bad, so most people just end up using the mobile site.