This seems like the entirely wrong thing to optimize. There are so many other opportunities for Facebook to monetize:
- group buying around deals, or group buying in general
- "Pay by Facebook" Facebook Connect based payment system
- Facebook Presence based loyalty programs
among many other easier things than gifts. Gifting does not seem like low hanging fruit.
This is fundamentally social and something that pretty much only Facebook can do. I know that there are a lot of companies trying to compete in the loyalty, group buying, and payment platforms.
Yes, but Facebook has a billion users and the ability to make the right relationships with literally every card processor. And, group buying is inherently social. I don't see why these aren't at the top of Facebook's list for things to try.