I recently tweeted (late afternoon US CDT) a Daily Deal for a book by a living author. The author replied, lamenting that if he had known earlier in the day he could have notified his followers on Twitter & FB early. This would have (obviously) driven some number of casual Logos users to the site that day.
Suggestion: As part of the script that posts the Daily Deal each morning, email a notification to the (living) author, allowing the author the opportunity to promote the sale early.