Anyone who likes Seamless on Facebook receives the credit.
The move appears somewhat desperate until you couple it with the timing: It's freezing cold in many of Seamless' markets right now and that means people don't want to leave their homes to eat. This is a good time to lock in loyal customers.
Plus, following the launch of Graph Search, which generates search results based on your friends' likes, advertisers are waking up the fact that the brands with the most followers are going to "win" the most searches.