Chicago's entrepreneurs may be poised to score an increasing share of the roughly $400 billion monthly US retail sector. To wit: venture capital investment increased by about 450% from 2010 to 2011, according to Built in Chicago. In that time, more than 25 e-commerce companies in the Windy City scored funding. Last fall, in a vote of public-market confidence, the market rewarded social-coupon giant Groupon with the second-biggest IPO in tech history, at a whopping $12.5 billion. That minted plenty of new millionaires, soon to be angel investors with particular expertise in social, local commerce. And among many smaller-scale projects from innovation-boosting groups throughout the city, a new tech incubator, dubbed "1871" for the year of Chicago's phoenix-like emergence from a major fire, is being built in the historic Merchandise Mart with millions of dollars in state backing.