The hottest area of retail these days might be so-called online-to-offline sales, as represented by companies such as Groupon and rival LivingSocial. Founded in 2007, LivingSocial now claims 85 million users, and reportedly takes in more than $50M in monthly revenue. LivingSocial CEO Tim O’Shaughnessy chats with North Bridge Ventures’ Dayna Grayson is this MIT Enterprise Forum of Cambridge event. Register here.