Yes, I did a Groupon feature. I was the first massage therapists in Cincinnati to be featured, and just the 3rd business in town. I didn't know the ramifications of big, big discounts, but 2 years later that has changed.
I did the Groupon massage on a whim. I worked for 25% of what I normally do, which is what most businesses do when they do Groupon. You offer 50% off, they take 50%, and WHAM! You're making a few bucks an hour.
Yes, I do have a few loyal customers. I can tell you that almost all of my clients were wowed by their session-they told me so. I treated everyone as if they were a potentially new full paying client.
One of my regulars stopped coming to me since his wife "just keeps buying me massages on Groupon!" One acquaintance of mine, an LMT, has been featured several times on both Groupon and Living Social. Why? Because the clients don't come back if they're not getting an inexpensive massage.
It's sad, really sad. Having analyzed my own spending habits, and realizing that I would buy a Groupon with no intention of returning to said business, I refuse to buy them. Because businesses are featured so that they can obtain new clients, not break even on the service they perform.