Remember the innocent, students-only Facebook of 2005? Without pictures, without video... without Mom? Well, judging from this visualization, those youthful days are long gone. The Facebook that we have today is an international force, with half a billion members, thousands of apps and an increasing volume of functionality. Take a look at this viz to see how popular Facebook is in your neck of the woods.
Despite Facebook's phenomenal success, there are still over 200M people in North America who have yet to join. Universal adoption is nearly impossible, but there is clearly room for growth. Outside of North America and Europe, the story is entirely different. Massive populations in India, Brazil and Indonesia have yet to be swayed into the Facebook camp, partly due to the popularity of other sites, like Google's Orkut. These people will decide whether Facebook goes global, or remains a club of the English speaking world.
Thanks to Robert Morton for the visualization.