A big rap on Groupon is that it brings in one-time customers that most retail businesses have no idea how to convert. If it led to a steady uptick in business, companies would be cheering. Right?

But can you have too much business?

Chef Geoff‘s uptown location used to have a terrific happy hour. You could come in, plop down at the bar, order a Super Mug, watch the news or a game, and hang out. My last memory of Tim Russert was on a bar stool at Chef Geoff.

That was Before The Groupon.

The Groupon brought in a new customer base–and a noisy, bustling happy hour made up mostly of law students from a nearby university. Now I have nothing against grad students (or college bars), but it’s a different atmosphere. And empty bar stools are hard to find.

I don’t know whether Chef Geoff is happy with its new business model. Or whether it’s impacted their dinner numbers–which is what generates the real revenue. What I do know is they sent an e-mail in June saying that the schools were out and it was a good time to come back in.

Maybe you can’t have too much business. But you can have too much of the wrong customers for your core market.

Photo by Mo Riza (Flickr).