Something not a lot of people may realize about Groupon is that they have a separate department called Groupon Grassroots that aggregates all the deals that go to help charity.
Some of these are the traditional kinds of deals, where you buy something and a portion is donated to charity. For example, as of this writing there’s an auction selling hammocks where 100% of your purchase price goes to the non-profit organization that
Others aren’t “deals” in the sense that you buy something and a portion is donated to charity. Rather, it’s a “deal” in that you donate to a good cause, and if enough members of Groupon do the same, then the combined donation is triggered and sent to the needy cause, in a crowdsourcing-type model.
Groupon maintains a regularly updated blog here where you can learn about new initiatives.