Groupon competitor Yipit comes out with all guns (and some charts!) blazing today, analyzing Groupon’s business in Boston. It does seem notable that the cost to acquire a Groupon subscriber is something like $30, while their quarterly revenue per subscriber is $14. (That being said, customer averages are always weighed down by the one-time customer, and businesses rely on the repeat “power user.”) And at least the company had $810 million to pay to backers and executives! Buying a printing press to make dollar bills at home would be much more work, it turns out.