The problem is, after two full years of participation I've made just six purchases from Groupon. Only two of these purchases saved me a significant amount of money. One merchant still hasn't delivered my goods. You might say, fulfilling orders is the responsibility of the merchant not Groupon; but I suspect what pushed the merchant's order fulfillment team over the edge was having to process a large number of Groupon orders that had the same expiration date.
Two years means over 700 emails from Groupon have entered my inbox. The hit rate is less than 1%. It's not worth my time, so I have unsubscribed. The clear inference is that Groupon's business model doesn't make sense for most merchants, even on a one-shot basis.
From a business perspective, Groupon has been doing poorly. It IPO'd in November 2011, and the stock price has fallen 87% from its peak. One reason: Groupon's accounting, which has often been inaccurate. It's been a problem since the beginning.
Wall Street, of course, doesn't care about the decline of Groupon post-IPO. Morgan Stanley, Goldman Sachs, and Credit Suisse got their money from the IPO up-front -- as they did from Facebook's IPO. Friends, never forget that Wall Street is always trying to sell you something. Buying it might not be in your best interest.
I still get daily emails from Woot (now a subsidiary of Amazon), but I've begun to question those too.