A quick Google search found many health-related Groupon deals, most notably a bundled package from Spinal Health Care in Cordova, TN. The September deal offered back-pain sufferers a consultation, exam, digital x-rays, a spinal adjustment, and a 30-minute massage for $39—93% off its $575 total value. According to the Groupon page, 145 people purchased this deal.
Even with such an extreme discount, I'd call Spinal Health Care's Groupon promotion a success. For presumably much less than a traditional advertising campaign, the chiropractic practice got 145 people familiar with their brand, physicians, and patient experience. And if some of those patients were diagnosed with a problem that required treatment, they may have booked subsequent appointments at full price.
(Of course, this is assuming that the practice's patient experience is up to snuff. There's no point in attracting hundreds of new patients if they aren't satisfied with their care when they get there.)
In the days of retail health, the possibilities for healthcare organizations to use social spending sites are limitless. Discounted flu shots, physical exams, and other types of screenings will be popular with today's price-conscious health consumer—especially if they are suffering the consequences of a previous Yoga or Indian food deal gone awry.