($240,000,000 / (0.016 + x)) != $15,000,000,000

Attention world: Microsoft did not pay $240 million simply for a 1.6% stake in Facebook. They paid $240 million for a 1.6% stake in Facebook and the privilege of being Facebook’s only ad supplier for visitors from outside the United States. So unless you’re valuing that privilege at $0, stop spreading this ridiculous valuation estimate around.