Deal discovery and daily deal pioneer Groupon is at Mobile World Congress, providing us with some fresh insight into how well its mobile platform is performing — and it’s going well for them, particularly in North America.

Groupon today announced that its mobile apps broke records in December 2011, with 25% of all of its deals in the region purchased via a mobile device.

The company saw over 26 million app downloads of its Groupon Now app, helping to increase its mobile userbase by more than three times to 9 million, tripling its figures since December 2010.

Increased app usage isn’t just limited to consumers either, merchants are taking to their mobile devices to check their analytics and see how well their deals are performing in real-time. In fact, more than 12,000 merchant partners used Groupon’s merchant app to redeem vouchers and check purchases on their iOS and Android smartphones and tablets.

Earlier today, Groupon announced that it has expanded its partnership with Nokia to preload its apps on certain Nokia devices. This will help boost the amount of interaction Nokia users have with the daily deal service by offering location-based services to devices.

Mihir Shah, VP of Mobile at Groupon believes this year will really see Groupon focus getting it users on mobile, having concentrated on releasing cross-platform apps and expanding the regions in which it operates last year.

Groupon’s mobile services are available in Europe and Asia also, and whilst they aren’t showing the same figures as Groupon customers in North America, usage is impressive given the fact that the platform in those regions is still less than a year old. In the UK, 8% of all purchases were made via mobile in December 2011, with customers in Singapore accounting for an impressive 19%.

In January, Groupon and Deutsche Telekom announced a partnership that will see the daily deals service distributed as standard with the telephony giant’s smartphones across Europe. It is the first time that Groupon has partnered with a mobile operator, which doesn’t require customers to download an app.

The first handsets featuring Groupon services are scheduled to be available during the first half of 2012.

It’s clear that many smartphone users are finding it easier to open the Groupon app on a given day and using it to make spur-of-the-moment purchases. We don’t know if they still receive the daily emails, but if they are received on the same device, it could spur usage on both smartphones and tablets.