"There's a lot of excitement about the Groupon IPO, but to have a valuation of $20 billion is amazing for a company that is still having significant losses," says Chadbourne & Parke LLP partner Lori Hoberman in this video interview with The Deal Pipeline. There are also questions about the sustainability of the online coupon maker's business model, points out Hoberman. For more of our conversation with her about social media IPOs, including pricing issues, watch "LinkedIn underwriters were conservative." - Mary Kathleen Flynn