For the millionth time, FB did not "pay" 1 billion, they gave Instagram an unspecified (and probably very low) amount of money and a quantity of pre-IPO stock.

For the millionth time, FB did not "pay" 1 billion, they gave Instagram an unspecified (and probably very low) amount of money and a quantity of pre-IPO stock. FB paid almost nothing, their risk is trivial, Instagram's investors however have had their bet on Instagram converted into a bet on Facebook.