Back in December, Google made a bid for the social e-commerce company Groupon that valued the company at billion, according to press reports. By the end of the month, TechCrunch and others were putting a nearly billion value on the company based on a new round of venture capital (VC) funding. Two weeks into the New Year, The New York Times reported that Groupon was talking to Wall Street bankers about an IPO that would value it at billion. By March, Bloomberg had upped the IPO price tag to billion. How does a company that helps people buy $30 worth of Chinese food for $15 see its estimated value more than quadruple — to $25 billion, no less — between Thanksgiving and St. Patrick’s Day? Must be Internet II: Return of the Dot Com Bubble , right? Not necessarily, say Wharton faculty and other observers. “I would put myself in the class of bubble skeptics,” says Luke Taylor , a Wharton finance professor. “People have knee-jerk reactions when they call something a bubble; it’s a non-explanation.…