I suspect that people don't trust a merchant-supplied coupon. A also suspect this is why when you Google "landsend coupons" the #1 site is a UGC coupon-sharing

I suspect that people don't trust a merchant-supplied coupon. A also suspect this is why when you Google "landsend coupons" the #1 site is a UGC coupon-sharing site and #2 is the merchant's own site. By every traditional measure, the merchant's page should outrank the coupon site. Why would you trust a coupon sharing site more? The merchant has an incentive to only give you some token discount, whereas the "crowd" has no such incentive. So you're more likely to trust the crowd in this scenario.