The Wall Street Journal reports on the boom of online coupons:

Practically unknown a year ago, social coupons have boomed by offering consumers another route to discounts while providing small-business owners guaranteed revenue and a flood of new customers.

Groupon, the leading online coupon provider, has seen rapid growth as customers use broadband to look for discounts on a variety of goods:

The Chicago-based company says 35,000 businesses are currently waiting to be featured on its site, with 700 new U.S. businesses approaching it each day.

"For every business we feature, we pass on seven," Groupon Chief Executive Andrew Mason said. The company, which generally keeps 50% of the coupon price, expects to do $400 million in revenue this year. About 13 million people have registered to receive the company's emails.

Some rivals, such as LivingSocial of Washington, D.C., have also begun to analyze data they collect from customers to discern buying patterns and better tailor deals for each business so that capacity isn't a problem.

Read more here.