The title forces the reader first to think about what a crime actually is. Most would picture literal crimes such as Raskolnikov's murder of the pawnbroker. However, Dostoevsky forces his readers to consider other crimes that are not always visible.
In regards to the "punishment" in the title; again, the reader must interpret beyond the literal punishments such as one serving time in prison. Raskolnikov's true punishment is his inner conflict, the guilt which leads to physical and even mental illness because of its consumption of Raskolnikov's soul.
Moreover, the reader must also consider, in general, what makes a punishment fit the crime? How much time is enough for one to be punished for a crime?