My understanding is there are 3 reasons. 1)The authors want to build a brand for themselves rather than just provide you with recipes. This helps to get further opportunities for them and differentiates their cookbook/site from others in a very crowded market 2)A lot of people read cookbooks as books rather than just when they are cooking and this philosophy seems to have been copied over to recipe sites 3)Copyright. Istr reading somewhere you can't copyright a recipe whereas you can pursue a claim against someone who plagiarises the non-obvious text parts. It's something like that.