A background amount of insulin for normal functions of the body without food and a burst of insulin "on demand" when food is eaten. People without diabetes can trust that their pancreas will produce this insulin for them. People with diabetes need to take insulin as similar as possible to the way their pancreas would produce it if it could.
With multiple daily injection therapy, it is not always clear how much insulin is being used for background and how much is being used for food. In insulin pump therapy, the two are clearly separate. Insulin pump therapy allows you to set a basal rate, or background insulin, to be delivered continuously throughout the day and night for the normal body functions. When you eat you can then give a bolus, or delivery of insulin, "on demand".
When you exercise, you can reduce the basal rate so that your blood glucose does not drop too low. Or when you are sick or have an infection, you can increase the basal rate so that your blood glucose does not go up too high. You can also increase or decrease your meal bolus based on the foods you choose to eat.
Additionally, the pump uses only fast-acting insulin. You will not need to follow as rigid a schedule as you did before, because there is no long-acting insulin telling you when you should eat or when you will need more insulin.
Sound exciting? It is exciting... not only can your blood glucose be easier to manage, but your lifestyle can be easier too.