There was lots of discussion about this last year, particularly that as they exist in a market longer, they have to spend more to find new customers (because th

There was lots of discussion about this last year, particularly that as they exist in a market longer, they have to spend more to find new customers (because they start exhausting the pool of businesses willing to "test" their service.) http://betabeat.com/2011/06/groupons-business-is-decaying-in-its-established-markets/ http://betabeat.com/2011/06/groupons-business-is-decaying-in... Is it true? I don't know (hence my use of the word "may"), but it's certainly a concern for Groupon and other local business services that have to spend a lot of sales people to target relatively small business customers.