Coupon sites...

How many of you use Groupon, LocalTwist, Living Social, etc. for skincare services? Do you become a return client because of your experience, or is it a one time shot? Or do you use the discount as a way to check out a potential new place and then make your decision? Please tell us your thoughts on this new way of marketing... pros, cons... should The Bathery jump into this? Give us your feedback!