We've been featured on Groupon locally before (NYC) and I have to say their customer service is top notch. It's unreal how well their reps take care of you and make sure your business is setup and ready to go. Of course it's in their best interest that the deal goes smoothly, but still, it was nice to see so much attention. Our sales rep was answering questions on our behalf at 3AM EDT.
I'm glad they're doing so well. They took a good idea, executed it well, and take care of their customers. Business 101.