Is Facebook crazy? First it bought WhatsApp, a company few Americans had heard of, for a hefty $19 billion. Now it's buying Oculus, an equally obscure firm, for the slightly-less outrageous sum of $2 billion.

In case you're not familiar with Oculus, they're the company behind the Oculus Rift, a virtual reality headset that turns video games into 3D experiences. The thought of Facebook getting into virtual reality might have you questioning Mark Zuckerberg's grip on reality. But it actually makes a ton of sense. Here's why.

From the moment Facebook was born, the service was always an addition to your social life. Stalking an ex? Look to Facebook. Reviewing job candidates? Investigate their Facebook profile. Casual online games? Facebook, Facebook, Facebook.

The Rift has potential to define next-generation Facebook games. But Zuckerberg has his sights set on a much grander idea about social interaction. He doesn't want Facebook to be an app you use to socialize with people while they're out of physical range. He wants Facebook to become the app you use to have actual, real-life social interactions.

"By feeling truly present, you can share unbounded spaces and experiences with the people in your life," Zuckerberg wrote in a blog post. "Imagine sharing not just moments with your friends online, but entire experiences and adventures."

It's hard to imagine a future in which Facebook is even more dominant over our social lives than it already is. Still, Facebook needs to show that it's still the visionary product it was when it all began a decade ago.