I first stumbled upon duck fat as an everyday kitchen ingredient about five years ago. I was testing a particularly chefy set of recipes for a magazine, and two of them called for a tablespoon of the stuff. Since I couldn't find it anywhere locally, I ordered rendered duck fat from an online provider that only shipped in quart and gallon containers. There was a lot of extra duck fat in my fridge when the project was over. And it wasn't hard at all to find something else to do with it.
If you've ever cooked with duck fat, you know it's got a very soft and loose consistency, as if it could melt at any second at room temperature. The softness actually reminded me a lot of vegetable shortening and I'd been making pies at the time. The duck-shaped light bulb illuminated.