There have been many anecdotes lately from business owners about how Groupon, the online coupon site for local businesses, isn't actually that good for business, but now there's some data to back it up. According to a study out of Rice University, 42 percent of businesses who participated in a Groupon deal said they would not do so again, even though the majority of those who participated said their promotion was profitable.

The study was conducted by Associate Professor of Management Utpal M. Dholakia, who surveyed 150 businesses in 19 cities that ran completed Groupon promotions between June 2009 and August 2010. He found that 66 percent of those businesses were profitable, while 32 percent were unprofitable. Restaurants were the most unprofitable category, describing Groupon customers as "entitled," poor tippers, and definitely not repeat customers. Spas, on the other hand, were the most profitable (though their Groupon-using customers were still bad tippers).

Those that were profitable reported a high percentage of people buying more than the coupon's value (50 percent, compared to 25 percent in the unprofitable group) and those purchasing a second time (31 percent versus 13 percent). Still, when analyzing which factors make a promotion profitable, it all came down to employee satisfaction.

However, when asked whether they would run a promotion again, almost half (42 percent) said they wouldn't. That number includes one in five of the businesses that ran profitable Groupon promotions.

"There is widespread recognition among many business owners that social promotion users are not the relational customers that they had hoped for or the ones that are necessary for their business’s long-term success," reads the report. "Instead, there is disillusionment with the extreme price sensitive nature and transactional orientation of these consumers among many study respondents. "

Dholakia says that Groupon and sites like it benefit consumers more than the businesses that offer them. That may seem like an obvious conclusion, but he also says that these sites won't be sustainable long-term until businesses get a better deal.