Guess who implemented Groupon outside of the US? The Samwer brothers. They created CityDeals, that merged with Groupon. One of the brothers has been in charge (unofficially, I think) of Groupon's international operations ever since.

Edit: Actually, Marc Samwer was head of international operations until earlier this year: http://gigaom.com/europe/marc-samwer-out-as-groupons-interna...