In one month, Groupon’s skyrocketing revenues suddenly tanked by 30 percent—and it just happened to be the month of the site’s widely hated Super Bowl ad, according to data compiled by TechCrunch. The blog cited calculations based on every deal posted to Groupon’s site over the past year. After strong growth in 2010, especially at year’s end and into 2011, monthly revenue abruptly fell from $88.9 million in January to $61.7 million in February. It’s not like Groupon had dropped off the radar. In fact, the opposite might have been the problem. After running a Super Bowl ad that mocked the Tibetan cause (part of a series of similar ads), the site was battered by critics. Groupon defended the ads at first but eventually switched gears, pulling the spots and reportedly ending its short-lived relationship with Crispin Porter + Bogusky. So, is this proof that not all publicity is good publicity? Or are there bigger issues behind the drop, such as holiday-spending hangover, daily-deal fatigue or increased competition from rivals like LivingSocial? I guess we’ll find out when the next few months’ worth of numbers come in.