It let's you enter the ingredients you have and provides recipes that include those ingredients.  You can even pare it down to number of ingredients in the recipe and what type of dish it is.

This is a great problem solver when you have some leftover fresh produce or a can of tuna you never knew what to do with!

Personally I'm excited to use it to find recipes where I can use the herbs from my new herb 'garden' (aka pot) I just started!