This seems to be an absurd number that they are throwing out there. Perhaps it is a psychology tactic to get people to accept a $15B IPO. I'm not sure how Groupon can maintain this value as more and more people are beginning to associate anything with Groupon as cheap. Take for instance the deal they offered on Wednesday for the new Matthew McConaughey movie, once people saw the offer they immediately assumed that the movie was horrible.
It's very difficult to short sell a stock right after its ipo. 30 days after the ipo many more shares are available.
Whether or not the stock would be a short is up to you; however, I would take a look at how other "overvalued" names have done recently -- CRM, NFLX, and OPEN come to mind.
This prompted me to sign-up for Groupon for the first time today.
I laughed because it appears to be like Bits Du Jour (http://www.bitsdujour.com/) for everything - not just shareware deals. Bits Du Jour has been around for a LONG time - wonder why they never decided to do this for everything, not just software.
I unsubscribed from all daily deal sites including LivingSocial and BuyWithMe. I couldn't stand the daily barrage of emails that I received for products and services that were far less than intriguing.
Bits Du Jour seems a little more like a software-specific precursor to something like woot (http://www.woot.com/), with a daily discounted product to buy. Groupon's difference seems to be selling discounted coupons to physical businesses, sort of a mash-up of woot and restaurant.com.
It is with equal trepidation and excitement that I look forward to the IPO of Facebook and Groupon. Following LinkedIn is also going to be interesting.