What is Groupon and how can I use it?

I keep seeing GROUPON everywhere! So I thought I'd look into it. Turns out its pretty handy.

Each day, Groupon features an unbeatable deal on the best stuff to do, see, eat, and buy in your city. By promising businesses a minimum number of customers, we get discounts you won't find anywhere else. We call it "collective buying power!"

"I like today's deal - how do I get it?"
Just click "BUY" before the offer ends at midnight. If the minimum number of people sign up, we'll charge your card and send you a link to print your Groupon. If not enough people join, no one gets it (and you won't be charged), so invite your friends to make sure you get the deal!