Groupon (a play on “group coupon”) is a company that offers high-discount coupons to people in a particular geographic area — typically to local companies like restaurants, dry cleaners, clothing stores, or salons. The coupon becomes valid only if a predetermined number of people purchase it on a given day.

Groupon has been lauded for its particular twist to local online advertising, leading to hundreds of new Groupon competitors. Some are tied to news companies, which have traditionally been dominant players in the local advertising market.

Groupon was launched in 2008 in Chicago and spread quickly to more than 150 markets in the United States and Canada and more than 100 in Europe. A Groupon study claimed the company was on pace, as of 2010, to be the fastest company to reach $1 billion in annual sales in history.

For a local business, Groupon offers a deal different from traditional media outlets. Companies offering the coupon do not pay upfront; instead, Groupon takes about half of the revenue generated by coupon purchases. Since those coupons are often for roughly 50 percent off the normal price, companies often end up generating about one-fourth the revenue that traditional sales would. That has led some businesses to report a negative experience when Groupon sent them more customers than they could profitably handle. But many companies consider Groupon’s ability to put their product in front of so many customers — in particular, so many new customers — that they’re willing to accept the lower revenue per sale.