These points are courtesy of Food & Wine:
"While the difference between stock and broth is minimal, the two cooking liquids are made from different ingredients. According to
F&W Executive Food Editor Kate Heddings, stock needs to be made with bones, in addition to a mirepoix, a mix of carrots, onions and celery. At its most basic, broth is simply any liquid that meat has been cooked in. However, the most common way to make broth is take stock and add additional meat, vegetables and salt to the liquid itself (traditional stock is unseasoned)."
"Stock develops a substantive body as the bones and any attached cartilage release collagen and gelatin into the liquid while cooking. If you happen to make broth without using stock, it will have a different texture and lack the sumptuousness that stock provides."
"'Broth is something you sip and stock is something you cook with.' Stock is used as a base in sauces and soups, but its role is to provide body rather than flavor. Broth, on the other hand, is designed to be flavorful and tasty enough to simply drink by itself, which is why the additional salt is so important."
That's more than I ever wanted to know.
