I'll post a more legal version of this soon, but here's a the gist of what I know and think.
Recipes come under a bit of a gray area in the legal copyright arena.
Legally, a recipe itself (the ingredients) isn't so copyrightable, so to speak. The COLLECTION of recipes, as in a cookbook or a blog, IS. You can't copy a whole cookbook and call it yours. The description and prose that goes along with a recipe still belongs to the writer, too. Don't copy that stuff.
If you send me a recipe and it is from another cookbook, please make reference to that original book and author, whether or not you have changed or adapted the recipe to your own liking. Karma is karma and we want to keep her on our side. (To paraphrase "My Name is Earl.")
If you send me an original recipe that YOU created, please tell me your name and if you have published it before and where. I will keep your name associated with that recipe. If you are sending me anything, you are acknowledging its potential use in this site and inclusion in a cookbook, with no compensation other than a credit and maybe a free book, when and if it is published. (I prefer to think, when.)