It seemed to be a match made in Internet heaven. In late 2010, Google made a $6 billion bid for Groupon, the Chicago­based company that e­mails daily coupon deals for local goods and services to consumers around the world. (If enough people sign up, the daily deal “tips,” meaning the coupons are issued; otherwise, the deal is called off.) Google was looking for opportunities to branch into local­search advertising, and Groupon appeared to be the perfect fit.