Actually . . . crutch words slip into sentences in order to give the speaker more time to think or to emphasize a statement. Over time, they become unconscious verbal tics. Most often, crutch words do not add meaning to a statement.
Actually is the perfect example of a crutch word. It is meant to signify something that exists in reality, but it is more often used as a way to add punch to a statement (as in, "I actually have no idea").