The key for Groupon is not just Q4 revenues but Mobile. This is the company that seems to be monetizing mobile the most among ecommerce/internet companies (already, even in their Q3 numbers there was significant mobile revenues, more so than many of the much larger firms).
The larger firms are currently still struggling to monetize mobile it seems.
If Groupon can right the ship then I would be shocked if one of the larger names did not make an acquisition play this year. The list of potential suitors is quite large and has been discussed on this board a lot.