Is there a patent on Groupon.com?

Groupon says they have a patent on the process. See Coupon Wars: Groupon Gets Ripped Off.

On the other hand there are a lot of competing sites out there already. See Groupon Clones pop up like mushrooms.

The major problem you face has nothing to do with either of those issues. Groupon is currently being sued in a class action lawsuit over expiring gift certificates. See the Class Action Complaint. There are numerous laws that cover the purchase of gift certificates and in the Groupon model a gift certificate expires after a fixed period of time. This violates some laws. Be forewarned.

Groupon may have some code patents but it is impossible to patent idea of group buying power. Think Costco...

In had built a website in 2001 that awarded cashback to members when they shopped online. A few months after I sold it to a an engineer from Microsoft, I received a letter from some firm claiming it was their patented technology... Fortunately all I had to do is give them a call and let them know I was not the owner of that site. If someone wants to sue you, they will do it whether they have a case or not. All they need is money for lawyers. Less then a year later Microsoft launched Cashback portal (http://www.bing.com/cashback).

Here's more on Groupon and possible competition: http://gigaom.com/2010/04/08/homerun-like-groupon-but-ridiculously-social/

http://tippr.com/ has many many many group buying patents (check their footer). They bought the IP of a failed group buying site funded by Paul Allen.

In your shoes, I wouldn't sweat it. There are a ton of (well funded) people diving into the space. They wouldn't do it if they thought they were going to get sued for copying/iterating on the idea.

Groupon says they have a patent pending. It will either publish 18 months after they filed it, or they've said they'll never file a patent outside the US and it won't publish until it issues (could be years). Take a look at the issued patents at the bottom of Tippr's home page before starting a business. They may or may not hold up in court, but it will cost millions to find out.

Groupon was recently sued for patent infringement. "Statecaster", you may want to look at U.S. Patent 7,672,897, Method of Community Purchasing Through the Internet.

i think what the have patented is the "tipping", it that it takes a certain amount of people to buy something before it becomes available ...

if you look closely, everything is copied from groupon except for this tipping thing ...