Groupon started in Chicago less than two years ago. It moved on to New York, then Boston and San Francisco and now the world.
The business model is one that can make even a cautious shopper jump at a deal. Every day the company sends out an e-mail with a special deal from a local company.
It can be 52 percent off a fitness program or 75 percent off food.
The whole thing was CEO Andrew Mason's idea.
"It is a little different because we only feature one business a day and we give people a really good deal on that business," he said.
But there is a catch: a minimum number of participants are needed to activate the coupon.
"I kind of make it a point to check and see what the daily deal might be," Los Altos resident Yvonne Wong said.
Wong checks because the deals come and go, lasting only a day at most.
"It is kind of a city guide masquerading as a deal site; the way we think of the service is a way for people to discover interesting new businesses in their city," Mason said.
That is the part about it Wong really likes.
"Maybe like two weeks ago I decided to do a Groupon date night. We pretty much did a ghost tour, a China Town Tour which was part of a Groupon deal and we also went to a restaurant I also got on Groupon for us," Wong said.
A good feeling, but is it good for you?
"Most of the offers are retailers who have been hurt the most by the recession. They are services, restaurants a lot of products that are suffering right now, they want to reintroduce their products o consumers and this is a way to get you in the door. I think the retailers are hoping once they are in the door they will keep coming back," Golden gate University consumer psychologist Kit Yarrow said.
So many businesses want to be featured on Groupon it is changing the way it does business. Now it is targeting specific deals to its customers, tailored to their profile and location.