WebVan, pets.com, etc.. are totally reasonable business plans at their cores (Deliver Groceries, ship pet supplies). Eliminating 10% of perishability is also a reasonable business plan. But it is unreasaoble to think that you can charge a 40$ markup on groceries or make 30% off a 10% revenue increase. 'Social Netowrk Coupons' will continue for a long time, groupon will not