Deal-a-day coupon company Groupon Inc. has hired away a top Google executive to be its chief operating officer as rivalry grows between the two tech companies.

The new COO, Margo Georgiadis, ran global sales and operations at Google Inc., overseeing the company's advertising business, its main source of revenue.

"Margo is a strong leader with a passion for helping small business owners and consumers," CEO Andrew Mason said in a statement. "We're thrilled to have her on our team."

The announcement's timing was meaningful: Also on Thursday, Google launched its own daily-deal coupon service, Google Offers, to rival Groupon.

Google had been in talks to buy Groupon last year but they broke off, reportedly because Groupon's board split on whether to accept the offer.

Groupon, which has grown quickly since its 2008 launch, has been raising money from investors and is expected to go public this year.

In December, the Chicago company opened a new office in Silicon Valley and hired a former executive as its chief financial officer.

In recent months, it has expanded to South Korea and the United Arab Emirates to hit a total of 45 countries. It also added Starbucks Corp. CEO Howard Schultz to its board of directors.