The more you hear Mark Zuckerberg talk about the future of Facebook, the more you realize that his vision is not that Facebook become the biggest community on the internet or the biggest web site on the internet, but to become the internet itself.
The key point, and the one thing you really need to accept to understanding where Facebook is going, is that Zuckerberg sees internet access as key to making his company — and society — stronger. The internet creates jobs, brings people together, can educate those in underserved communities, and even allow for things like remote surgery to save lives. It'll probably also make Facebook some money, too. If you take all of that as his starting point, the rest of Facebook's initiatives begin to make sense.