Zynga makes its money off "whales" because it's a freemium model, where heavy users pay for extra functionality. Facebook has an advertising model, where they b

Zynga makes its money off "whales" because it's a freemium model, where heavy users pay for extra functionality. Facebook has an advertising model, where they basically get paid for "unique users". So once a user views more than a few pages of ads a day, the marginal value probably starts to decline for them.