I am not a fan of the Groupon/Living Social Model. I fact I detest it. It just smells bad to me.
However - clearly the consumer's like it. So it has value. But this is a zero sum game which is so blatantly obvious that either I am stupid... or they are.
So have a read of the article from eMarketer. It does show some interesting dynamics of the two players.
Sadly it just approaches things from the consumer end not the supplier end.
But worth a read anyway