I think that selling at a $6B valuation makes complete sense.<p>It seems to me that if 40-50% off coupons were the magic key to retail success, they'd have been discovered by retailers already.<p>Groupon's coupons have already been getting worse... more of the "Get $50 worth of x for $25" which is not all that compelling if the overall purchase will be $100+.<p>Groupon has done a brilliant job of marketing, but I don't think it's sustainable as is. Groupon clearly has a superb sales team and genius marketing, but if I were an investor I'd want to cash out now, even at a $1B valuation.