Explain the difference between act utilitarianism and rule utilitarianism?

First, the definition of utilitarianism according to John Stuart Smith, is to increase happiness, or utility.  "A person's utility is what satisfies the person's needs and values."  For each action, we consider the impact on utility and  judge the action by it's net impact.  This is called "act utilitarianism."  The utility principle that would not be applied to individual actions but to general ethical rules are considered to be "rule utilitarianism."  An objection to act utilitarianism is that it does not recognize and respect individual rights.  It has no absolute prohibitions and can allow actions that many consider wrong or bad.  As an example, if I were to justify taking the life of a bad individual and then donating his/her organs to a village in need, then this could be justified as a utilitarianism act.  A person has no protected domain of freedom. Rule utilitarianism endures less than act utilitarianism and it's problems.  For example, stealing and murder of the masses will affect the security and peace of all, you can determine that this action is considered a rule utilitarianism.  We can state the particular rules in terms of rights to property and life.