Maybe in the U.S. I was in Asia few months ago and I came across people who were new to Facebook. Facebook still has a honeymoon period with those people who just discovered their 'new' platform. Given the massive population in Brazil and India that would be a sizable chunk of users.
But financially problematic for Facebook. They built an expensive cost base that relies on advertising for users with high nominal income. Advertisers pay far less for Indian and Brazilian users. That's why the decline in US users is so important, not because they lose traffic but because it's directly linked to revenues.
