Using Groupon to sell your products and services falls loosely under the umbrella of Internet Marketing. It is not a traditional Internet marketing activity, rather, it is a one-time sales/promotional activity...hence the term loosely.
Before you actually use Groupon, do take the time to evaluate whether Groupon will work for you or not. Regardless of how you proceed, we highly recommend reading Inc Magazine's article on the 10 Pros and Cons for Using Groupon. Read at: http://arni.ma/gp-con.