Our fabulous social media guru, Anthony DeRosa, doesn’t use Groupon, and neither do I, and neither do any of the people in our social circles, that we know of. Now we’re guys, while Groupon skews female. And most likely we do know people who use Groupon; we just don’t know who they are. But the fact is that at heart it’s pretty uncool. That’s fine — many hugely successful companies are uncool and based on saving people money, up to and including Walmart. But here’s the problem: Groupon can’t afford to be uncool just yet, because it needs to do one last big capital-raising round at a high valuation in order to get the cash it’s going to burn through in the coming year or two.

Henry Blodget has some smart analysis today, concluding that “if Groupon raises a boatload of money in an IPO, the company will be able to keep spending aggressively on marketing and not have to worry about running out of money or dealing with slower growth for a while.” So it’s important that Groupon is able to tell its high-growth, high-intrinsic-profitability story at least through its IPO.

But Groupon’s web traffic looks like it might be falling, and Connie Loizos has been talking to analysts, including PrivCo’s Sam Hamadeh, who increasingly, don’t buy it:

Groupon’s model simply doesn’t make sense, say the number crunchers. While the company’s early success was premised on customers spending an average of $15 per month — and being affordable to acquire — these days customers cost Groupon in the double-digit dollars to acquire, says Hamadeh, and they’re spending closer to $3 a month, with “every indication” that even that figure is declining, says Hamadeh.

The monthly spend per customer is a key number to look at. There doesn’t seem to be any doubt that it’s going down; the big question is whether it’s going to level off with Groupon becoming a big and sustainably profitable business, or whether it’s just going to approach zero.

Or, to put it another way, can Groupon make the transition from being a fun fad to being a basic part of the way people spend money on a monthly basis? I think it can. But in order to do that, it’s going to have to concentrate increasingly on targeting and on the quality of the merchants it chooses to feature.