Groupon and other deal-a-day coupon sites spend tons of money on Facebook ads. Since Greg (hi Greg!) works at Facebook, it'd be a gross breach of trust for him

Groupon and other deal-a-day coupon sites spend tons of money on Facebook ads. Since Greg (hi Greg!) works at Facebook, it'd be a gross breach of trust for him to reveal who Facebook's ad clients are. Zynga is a well-known example, often mentioned because they spend a ridiculous amount of cash on FB ads.