Groupon beats revenue estimates by Dan Primack @FortuneMagazine February 8, 2012, 9:27 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Groupon impresses in its first earnings report as a public company. Groupon GRPN today reported better-than-expected revenue today, in its first quarterly report since going public last November. The Chicago-based daily deals company reported $506.5 million in Q4 2011 revenue, compared to $172.2 million in the year-earlier period. Revenue also rose 18% quarter-over-quarter, with Q1 2012 revenue guidance of between $510 million and $550 million. . Gross billings rose 201% year-to-year, to $1.25 billion for Q4 2011. Despite the top-line merriment, however, earnings-per-share were a disappointing negative 3 cents per share, compared to consensus estimates of positive 2 cents per share. That likely explains why the stock is down around 15% in aftermarket trading. Or maybe that’s simply a reflection of the fact that Groupon shares had spike more than 20% over the past couple of weeks. Earnings call is scheduled to begin shortly. Should be interesting to see if CEO Andrew Mason is answering questions, given his penchant for going way off script.