- Horns do not seem to get awarded everytime you accept someone's gift.
*If you accept multiple gifts at once, your only the first friend you accepted a gift from will receive a horn. You should accept a gift, close the window, let Facebook do it's thing, then reopen your notifications (red button just above the top right of the game window) to accept the next one.
*Receiving gifts on a mobile device doesn't award a horn to the sender.
This information hasn't been entirely confirmed, but so far it's the best we have. Please post any findings at Thread:159843