Counterpoint: http://www.businessinsider.com/groupon-analysis-2011-10?op=1

A note on this from a wildly successful hedge fund manager friend of mine -

"In my mind, there is very little fundamentally concerning here - sure, growth is slowing and conversion stats slowing but all the negative hype looks massively overblown by startup techies who don't understand retail/couponing/restaurant businesses. Based on metrics, Groupon is still a phenomenal business that is growing rapidly"