Monounsaturated fatty acids are one of several types of fats. That makes the fatty acid unsaturated. Because of their unsaturation, MUFAs are generally liquid at room temperature. They will typically solidify at refrigerator temperature. As with other fatty acids, MUFAs have 9 calories per gram.
Research seems to suggest that MUFAs are indeed good for heart health.
Platelets are one component involved in clotting blood. Blood clots in blood vessels can result in a heart attack or stroke. In addition, MUFAs may help dissolve clots if they happen to form. MUFAs may even make LDL cholesterol better. Researchers looked at LDL cholesterol and found that MUFAs increased a specific type of fatty acid found with the cholesterol.