Worth noting that the Google deal had a big asterisk tied to it. Groupon was burning (and is still) through tons of money. There was a very good chance that the deal could have been turned down due to an anit-trust case or held up in court for 18+ months. Both situations would have crippled Groupon. Going public was just as big a risk as accepting the $6B, the former at least got the early shareholders a pop on their money for 4x what Google was going to pay.

I am still bullish that Groupon can become a sustainable business. They are a brand that the local commerce market recognizes, and with that they can package plenty of other services such a POS systems to diversify their income away from just deals.