Accounting for a third of total sales in the US.
The daily deals service has now released Q3 results to show that one-third of North American transactions were made via mobile devices, a rise of nearly 30 per cent year-on-year.
Revenue increased 32 per cent year-on-year to $568.6m, rising from$430.2 million in Q3 2011, with North American revs up 81 per cent year-on-year.
The firm boasts 200m subscribers and 39.5m monthly active users, a 37.5 per cent increase year-on-year.
Looking ahead, Groupon predicts Q4 revs will hit $625m and $675m, a surge of between 27 per cent and 37 per cent compared to Q4 2011.