Being enlisted to get people to click on more ads. (With apologies to Alan Ginsberg).

OK, Groupon has revenue and it's growing fast. The company had revenue of $713 million last year and $644.7 million of revenue in the first quarter of 2011 alone. It employs more than 7,000 people and has 83 million subscribers in 43 countries.

It's a worthy IPO candidate, but a valuation of $30 billion for a company that lost $450 million in 2010?

The group buying space is going to get very crowded in the coming months, with Living Social and others in ramp-up mode. And I'm struggling to see how someone like The Google doesn't figure out a way to go after the same local advertising market. Or whether advertisers drift away for something that offers higher margins.

But maybe it just bugs me that investors are willing to assign so much value to what is essentially a coupon company.