The old cost-saving measure of clipping pages from the backs of newspapers has been transformed into a multibillion dollar industry by the advent of Groupon, the online group coupon service. Felix Salmon, finance blogging editor at Reuters, and Andrea Woroch of Coupon Sherpa, talk to us about the history of coupons, reveal why they're such a boon to businesses, and dissect Groupon's business model.

Do you clip coupons? Have you used daily deal sites like Groupon and Living Social? If so, tell us about your experience!