If people are already doing it, that is no reason not to try something different =) Currently, major group buying happens on GroupOn and Buywithme, as well on their European copycats. However, they are pretty much limited to services, as the prices are easiest to rip-off a percentage cut. BuyWithMe e.g. takes 20-50% of the price for them. That doesn't seem right to me?

Sure, the biggest challenge is in convincing merchants to actually use it. However, I think I will start with own goods first (3 retailing companies here).

I will see to change that to be a more sales feature instead of technical.

Thanks for the great advices!