I've heard of that too. Because I've never liked the store bought pre-made salad dressings, ever since I started preparing my food myself, I have used ACV, olive oil and salt to dress my salads. I also use it to pickle all kinds of vegetables. One way or another I incorporate it into my menu almost daily.
Edit: Almost two years into the Primal lifestyle I have noticed many health benefits. I can't be sure if it could be attributed to consuming apple cider vinegar, or it's just a combination of eating healthier and regular exercise.