And its an interesting idea. Recipes can't be copyrighted and and recipes are generally derivative. The data is generally well structured, and fairly standardized (ingredients, equipment, instructions, photo, with optional fields for prep & cook time, servings, notes, difficulty, etc). But there are two primary issues:
1. Recipes don't really have a single inheritance. For example, I cook a lot & really enjoying cooking, but when I'm trying to make something new, I won't follow a recipe. I will read a bunch recipes, and try to understand the underlying ideas & steal the ones I think are interesting, then implement my own. So say I look up Tufo Matar find 3 recipes the make my own, if I want to contribute which recipe do I fork?
2. This may have been dealt with by the use of stars. when I was using forkthecookbook, there was no way of "bookmarking" recipes and the so users forked them, which lead to the results having huge number of identical forks. That being said it seems like the star system may resolve that. But currently it looks as though unmodified copies of the recipes still appear in the Forks list, which makes it harder to find benifical changes. Also it would be nice to have a history section with a message summarizing what changed.
All that said this does look nice.
Additionally, a nice feature to have would be to "import" a recipe, though since phrasing of a recipe is protected this gets a little bit legally complicated.