- Groupon S-1 Reveals Business Model Deteriorating --- Groupon is growing revenues. Fast. But what if you dig into the financials? This technical analysis suggests issues with margins, customer acquisition costs and "network effects". Not conclusive but interesting given all the hype http://blog.yipit.com/2011/06/03/groupon-s-1-reveals-business-model-deteriorating-in-oldest-markets/ 6 comments business