Here's a piece about what Facebook can do to justify its high valuation while Christopher Mims is a bit skeptical that Facebook can ever be a profit engine. But the thing you really need to keep in mind when thinking about Facebook's business strategy is that Mark Zuckerberg doesn't need to care what you think. Facebook is his. All his. Everyone else is just along for the ride.
Separation of ownership and control is integral to the operation of modern financial capitalism, but typically the CEO works for the shareholders, at least in principle.
With Facebook that's not the case. As I wrote at the time of the IPO, Facebook is entirely Zuckerberg's. Or, rather, because there are two classes of shares, Zuckerberg controls 57 percent of the votes. That's all the votes you need. And any time any non-Zuckerberg owner of class B sells shares (and why not sell, since Zuckerberg controls the whole firm anyway) they convert to class A status and Zuckerberg controls the company even more firmly. What's more, at the time of the IPO Zuckerberg stated his intention to avail himself of the company's status as a controlled entity to eschew any independent participation in the selection of directors. In other words, it's his company from top to bottom, and anyone else who owns shares is just a silent partner.
Now obviously all else being equal, Zuckerberg would rather have Facebook stock be expensive than cheap. That's a lot of wealth for him. But he's a rich guy, and rich guys are free to exchange wealth for other things they might enjoy. Very few people live their lives with wealth-maximization as their exclusive goal, and if Zuckerberg doesn't want to maximize Facebook's financial value nobody can make him.