As reported by Frisky Mongoose today, watching a "Letters to Juliet" film trailer for the required minimum of 15 seconds was enough to earn them 1 FB Credit! That's akin to being paid one US dollar!
Now, before you run to your game excitedly, only to get annoyed when you can't find your DotD -- and there will be a lot of you who won't have it -- here's the official word from Crowdstar as to why: "Deal of the Day only appears for select users in some regions. You may be in the Target market for some deals and not for others. The icon may not appear for you every day."