Maybe Groupon’s pending IPO doesn’t reflect their profits (or lack thereof). Or it’s possible daily deals sites aren’t as appealing to consumers as they once were. And even former employees are foretelling doom for — some — voucher sites. We’ve heard it all. That said, do we think daily deals are about to evaporate? Of course not! So while Groupon, LivingSocial, Gilt City and their ilk are all alive and kicking, let’s talk about how to be a responsible coupon user, by which we mean, a polite one. Think of this as an Emily Post-style guide to daily deals manners, if Ms. Post was alive today and interested in half-off bikini waxes.