111%, 72%, 33%, 10%: Groupon's sequential revenue growth over the past three quarters. See a pattern here? 95%, 75%, 46%, 28%: Groupon's sequential customer growth over the past four quarters. See a pattern here? 137%, 64%, 39%, 24% Groupon's sequential subscriber growth over the past four quarters. You get the picture. $215 million, $207 million, $190 million: Groupon's marketing expenditures over the past three quarters. (See chart below.) A drop in marketing spending has given way to lower growth in subscribers, customers and revenue. Can Groupon maintain lofty growth rates without spending so frivolously on customer acquisitions? I doubt it. Just take a look at what CEO Andrew Mason told employees in a rant a few months back: "We are spending a ton now because we're acquiring as many subscribers as we can as quickly as we can. We aren't paying attention to marketing budget (just marketing ROI) in the way a normal company would, because we know that even if we wanted to continue to spend at these levels, we would eventually run out of new subscribers to acquire. "We view this internally as a very large one-time expense, and then our job forever after will be to continually convert these subscribers into customers and to make sure our customers keep buying from us." >>11 Stocks to Play the Groupon IPO Given the drop in margins for Groupon and the decreasing rate of revenue per subscriber (deal fatigue?), Groupon could have its work cut out in achieving profitability. Sure, once the marketing expenses tail off, expenses will retract, leading to the higher probability of turning a profit. But the question remains: Is Groupon just a flash in the pan, or a real business that can grow organically without the haphazard marketing expenses that have propped up the company's key statistics? That's the end of the numbers. Here's the commentary: If you haven't heard, Groupon is being called by some as the biggest sham to ever hit the IPO market. Some have even said Groupon is "technically insolvent," or that the underlying business is built on "complex financial instruments." Let me be clear, I'm not a Groupon supporter, yet I think the media has been too quick to bash the company. In an article from June, I even spoke of how I felt the Groupon business model was flawed, citing the negative effects that a deal can have on a small business.