what is the difference between utility and usefulness?????
Utility refers to the satisfaction of human wants. However, it may happen that a commodity provide utility (satisfaction) but is not actually useful (infact they may be harmful). For example, commodities such as cigarettes, alcohol, etc. may provide utility to some people but are not useful in the actual sense; as the consumption of such products are harmful. These commodities are said to fetch utility, as they fulfill the satisfaction of their users (smokers, alcoholics). So, from this we can say that usefulness implies utility, but utility need not necessarily implies usefulness.
Usefulness refers to which extent something is useful and the utility is the quality of that piece in practical use.
Both are inter-related terms. In other words you can say that utility is a factor of usefulness term. Usefulness means having practical utility of a piece which is beneficial, pertinent and functional.