The Downside of Social Coupons Social coupons can appealing--but make sure you're prepared to handle the rush of new customers they can bring.

Make sure you put realistic caps on the number of coupons sold and apply expiration dates or blackouts that won't work against your best interests.

Social coupons--those offers from Groupon, LivingSocial and the rest that hold out big discounts if a set number of web users opt in to purchase them--make me think of efforts to split the atom: If handled improperly they can melt down, leaving nothing but a big hole in the ground where a lead-gen campaign used to be.

The most recent example happened overseas, where a social-couponing acquisition by Groupon had a serious fail over the New Year holiday. The company ran an offer of a traditional Japanese New Year osechi meal--made up of various dishes with good-luck symbolism--home-delivered from the Bird Café in Tokyo for $127, a big rebate off the regular price.