[eftpotrm]

I agree I wouldn't have turned down the buyout, but from what I understand they're certainly not easily replicable.

Sure, you or I could set up a site that offers all the tech of Groupon pretty quickly. Then what? The strength is in their large and proven sales force and network of contacts. That can and will experience churn and cross-pollination with competitors, but they've got a heck of a head start, huge brand recognition and the resources to try new parallel ventures to hedge against problems with their current offering.

Any of a number of companies could and did duplicate eBay's tech. Outside a few national markets where eBay dropped the ball (Japan, New Zealand), how many succeeded?

[apollo]

Ebay is a deceptive example; auctions inherently have powerful network effects. I think Amazon might be a slightly better example: tons of competition but still a lot of money to be made. There can be many winners in this market, and Groupon will probably be the biggest winner.