McDonald's is currently buying sponsored ads on Facebook to ask whether you "would check-in at a McDonald's restaurant". Considering that McDonald's does not currently provide offers for checking-in via Facebook Places, this appears to be a survey campaign. At the time of the screenshot, over 20,000 Facebook users completed the survey. ~30% of those users have already check-in to McDonald's (hard to believe?) and 43% would do so for a "good" deal.
This is not surprising: we know that people love discounts and anything with the word "free".
It is a different approach to advertising alongside Facebook Deals. Starbucks and H&M have run campaigns promoting their deals - McDonald's might well do that in the future, but for now it is more of a branded research project.