Except for the part where Groupon provides an amount of hand-holding for businesses, that G has neither history, nor reputation of doing.
Historically relevant datapoints: G has both a buying service[1], and an affiliate network[2], neither of which seems anything remotely close to the success that Groupon is enjoying already.
Like Twitter & Facebook, they have access to all the money they could ever want. Plus, Groupon's revenues are through the roof right now, right on par with Facebook's.
I mean, seriously, a $6 billion valuation (if real) is $20 in _profit_ from every man, woman, and child in the United States. Not revenue, not EBITDA, but true profit returned to investors in 2010 dollars. That is a through-the-moon valuation.
If that is the case, then why aren't the investors screaming bloody murder?
Except cash.
This was by far the best possible hope of returning money to the investors and shareholders. Their fiduciary duty is to return money to investors. They failed.
It was an absurd home-run valuation that any venture firm would be happy with. And they are all but begging Google to compete head-to-head. Remember that Google knows everything about you already (Gmail, Google Checkout, Google Maps...); it would be easy for Google to target a buying service not only to your city, but also to your exact buying habits.