What is the purpose of the electronic stability control in the Audi A4?

I noticed a button with the letters ESC on my Audi A4 dashboard. What does it do and when should I use it?

The electronic stability control (ESC) in your Audi A4 is designed to help you maintain control of your vehicle in slippery or emergency situations by applying brakes to individual wheels and adjusting engine power. It is important to keep this feature turned on at all times, unless you are stuck in deep snow or sand where wheelspin is necessary.