Prepping for its 100-day sprint to Tax Day in late 2011, Intuit, the maker of TurboTax, was looking to grow a Facebook fan base of roughly 50,000. It decided to build an app to test users' knowledge of tax-deductible items and then pledged to donate a toy for each person who completed the quiz. It made an investment in the low six figures on "Gaming for Good" that mostly went to charity and added 101,000 fans, according to VP-global media and digital marketing Seth Greenberg.

That story might suggest that it's possible to market on Facebook without allocating many dollars to ads, but Intuit didn't stop there. On Feb. 1, it bought one of the network's pricey "reach blocks" to deliver ads to 50 million users, including a poll about what they'd do with their tax refund. It drove the highly visible "people talking about this" metric to 170,000.