The AP is just the latest in a series of news organizations pulling off GroupOn’s business model and profitability masks to reveal shady Old Mad Smithers in classic Scooby Doo style:

It’s the latest twist for Groupon’s IPO, which was one of the most anticipated offerings this year. In June, after Groupon filed for the offering, the SEC raised concerns about the way it counts revenue. Then the stock market plunged.

Now Groupon faces concerns about the viability of its daily deals business model. The novelty of online coupons is wearing off. Some merchants are complaining that they are losing money — and customers– on the deals. And competitors are swarming the marketplace.

“Groupon is a disaster,” says Sucharita Mulpuru, a Forrester Research analyst. “It’s a shill that’s going to be exposed pretty soon.”

And how do small businesses feel?

Adding to growing customer discontent, Groupon, which was initially seen by small mom-and-pop shops as a way to drum up new business, was losing favor with some of them. Merchants began to do the cruel math on the daily deals.

Restaurants offering $50 of food for just $25 only collect $12.50 — not even enough to cover the cost of the food. Some businesses also complain that the deals for new customers anger long-time patrons. Others say that the bargains attract high-maintenance types who don’t turn into loyal customers.

“Your restaurants are full packed with people who aren’t making you any money,” says Paul Evans, a Kansas City marketing executive who advises clients against using Groupon.

To GroupOn’s brief defense, if you’re a small business doing business with anyone, do your fucking math. If it looks too good to be true, it usually is.